The Harvard Medical School Family Health Guide
Infections and Immune System Diseases
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Infections

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Vitamin E supplements

If you’ve been taking vitamin E supplements, you’re not alone. The positive results of early studies on the antioxidant led many to take it in hopes of preventing or slowing everything from respiratory infections to macular degeneration. But what proves hopeful in early, preliminary studies doesn’t always pan out in larger research settings, and vitamin E is a case in point.

Age- Related Macular Degeneration

Age- Related Macular Degeneration (AMD) is the breakdown of cells of the macula, the small part of the eye that allows us to see things sharply and in color. Little is known about what causes AMD, which is the leading source of vision loss in people older than 55.

Early observational studies showed vitamin E might help prevent macular degeneration. To test this theory, researchers recruited close to 1,200 participants between the ages of 55 and 80 to receive either a daily vitamin E supplement or a placebo for four years. Participants underwent annual eye exams to detect signs of development or progression of AMD and changes in visual function.

The results of this study showed the incidence of AMD was similar among participants in the two groups. In the vitamin E group 8.6% developed AMD, whereas 8.1% in the placebo group did. Though this study clearly indicates that vitamin E does not help prevent or slow the progression of AMD, the study period was short, so it doesn’t prove that vitamin E doesn’t help in the long run.

(British Journal of Medicine, July 6, 2002)

Respiratory Infections

Early studies showed that vitamins and minerals, particularly vitamin E, may boost immune response in healthy elderly people. With this in mind, Dutch researchers set out to investigate whether either of the supplements lessens the rate and severity of respiratory infections in the elderly.

The researchers enlisted 652 participants over the age of 60 and broke them randomly into four groups. Each day, they either took a multivitamin with minerals and a placebo, a vitamin E pill and a placebo, both a multivitamin with minerals and vitamin E pill, or two placebos. After fifteen months of follow-up, the researchers found that the rate of respiratory infections did not differ among the groups. However, those who took vitamin E supplements actually had respiratory infections that were more severe — they were longer, caused more symptoms, and restricted more of the sufferer’s activities.

(Journal of the American Medical Association, August 14, 2002)

February 2003 Update

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The Spread of West Nile Virus

West Nile virus is a viral disease — spread by the bite of infected mosquitoes — that can cause encephalitis, an infection of the brain and spinal cord. It first appeared in the United States in 1999, when 55 people became seriously ill and another 7 died.

There was a total of 66 human cases of West Nile Virus in 2001 — mostly in New York, New Jersey, and Florida — nine of which were fatal. Almost all cases occurred in August and September, but a few were diagnosed between October and early December.

Since 1999, the geographic boundaries of the disease have spread as far north as Maine; as far west as Montana, Wyoming, Colorado, and New Mexico; and as far south as Florida and Texas. This is a dramatic change from 2000, when it was only detected in New York, New Jersey, and Connecticut. And 2002 has seen at least 480 human cases and 22 deaths from West Nile in the country's worst outbreak since the virus first was first detected here.

Most likely, the disease will continue to move west. To slow its progress, the CDC is concentrating on teaching people to avoid mosquitoes and their bites as much as possible. When in places where there is risk of mosquito bites:

  • Use insect repellent containing DEET.
  • Try to wear long-sleeved clothes and long pants treated with repellents containing permethrin or DEET; mosquitoes can bite through thin clothing. Do not apply permethrin repellants directly to skin.
  • Whenever possible, stay indoors at dawn, dusk, and in the early evening, which are peak mosquito biting times.
  • Eliminate standing water sources from around your home. These are popular places for mosquitoes to lay eggs.

Most people who become infected with West Nile virus will have either no symptoms or only mild ones. The risk of severe disease is higher for people over 50. There is no evidence that West Nile virus can be spread from person to person or from animal to person.

September 2002 Update

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Hepatitis A Vaccine is Safe and Effective for Children

Hepatits A is a virus transmitted by contaminated food and is a common cause of inflammation of the liver (hepatitis). This illness may be associated with fever, yellowing of the skin and eyes (jaundice), loss of appetite, nausea, vomiting, and tiredness. In many parts of the world, hepatitis A is so common that almost every adult has been infected at some point in his or her life. A vaccine to protect against hepatitis A infection was licensed in the United States by the Food and Drug Administration in 1995 for individuals 2–12 years of age.

A recent study published in the Journal of the American Medical Association showed that the hepatitis A vaccine was highly effective in preventing hepatitis A outbreaks among a large group of children who received it. The study also found the vaccine to be quite safe. Out of the nearly 30,000 children who received the vaccine, no serious side effects were reported. Mild adverse reactions were reported in a small percentage of cases, including injection site reactions, fever, and rash.

Should your child be immunized? In the United States, there actually are certain areas of the country with higher than average rates of hepatitis A. Speak with your child's pediatrician because the hepatitis A vaccine is currently recommended for:

  • Children living in areas with consistently higher rates of hepatitis A. This includes 11 states where the prevalence of hepatitis A is greater than twice the national average: Alaska, Arizona, California, Idaho, Nevada, New Mexico, Oklahoma, Oregon, South Dakota, Utah, and Washington. (Routine vaccination can also be considered in six states where the prevalence of the disease is less than double but greater than the national average: Arkansas, Colorado, Texas, Missouri, Montana, and Wyoming.)
  • Children traveling to countries where the disease is highly prevalent. This includes all countries other than Canada, Japan, Australia, New Zealand, Scandinavia, and those in Western Europe.
  • Children with chronic liver disease or blood-clotting disorders.

April 2002 Update

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Vaccine safety: no link between thimerosal and neurodevelopmental disorders

Parents should feel confident and safe when having their children immunized. No evidence exists that proves a link between thimerosal-containing vaccines and neurodevelopemental disorders, such as autism, attention deficit-hyperactivity disorder, or speech and language delay. The Institute of Medicine recently reported these findings, consistent with the recommendations of the American Academy of Pediatrics.

Thimerosal, a mercury-containing preservative, was used for many years in vaccines to prevent contamination. Taking in a high dose of mercury is toxic to the human nervous system. But because of the increasing number of vaccines routinely recommended for infants, concern was raised in 1999 by the Food and Drug Administration that the total amount of mercury contained in the vaccinations could be exceeding the recommended mercury levels for infants.

Although there's no data to suggest thimerosal caused any harm, the American Academy of Pediatrics and the U.S. Public Health Service have requested manufacturers remove thimerosal from vaccines. As a result, most, if not all, childhood vaccines are now thimerosal-free.

The Institute of Medicine's recommendations emphasized the importance and continued safety of childhood vaccination. Parents should definitely be reassured that all routine childhood immunizations are in their children's best interests, as they clearly have been shown to prevent potentially life-threatening diseases.
November 2001 Update

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H. pylori Infection May Aggravate GI Injury in Patients Taking Low-dose Aspirin

Doctors commonly prescribe low-dose aspirin for the prevention of heart disease, but it may also be responsible for some potentially serious side effects when taken frequently. Among the most common of these are gastrointestinal erosions and ulcers.

A recent study in The American Journal of Gastroenterology sought to determine whether certain people taking low-dose aspirin — specifically, people infected with Helicobacter pylori, a common bacterium that can cause ulcers — are more susceptible to gastrointestinal erosions and ulcers than people who are not infected with H. pylori.

Researchers from the University of Texas Southwestern Medical School and Baylor College of Medicine recruited 61 healthy volunteers between the ages of 18 and 61. Of these, 29 volunteers were infected with H. pylori. Forty-six of the volunteers were then randomly selected to receive low-dose aspirin (either 81 mg daily or 325 mg every three days), while 15 received a placebo.

After 46 days of treatment, an upper GI endoscopy was performed on each subject to determine the extent of gastrointestinal injury. The researchers did not detect any injury in the stomach or duodenum (upper intestine) of the patients taking placebo. In the subjects taking aspirin, those patients who were infected with H. pylori were significantly more likely to have gastrointestinal injury than those who were not infected (50% vs. 16%).

However, there was no difference between the groups in complaints of pain, nausea, vomiting, indigestion, or heartburn. In addition, the difference in outcomes between patients taking 81 mg of aspirin daily and 325 mg every three days was not statistically significant.
The researchers caution that the results of this study may not hold for older people or those with gastrointestinal diseases such as peptic ulcer disease, because the volunteers were healthy and aged 61 or younger. However, this study does suggest eradicating H. pylori infection may help prevent gastrointestinal erosions and ulcers in patients taking low-dose aspirin on a long-term basis.
October 2001 Update

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Lyme Disease Update

Can antibiotics catch Lyme disease before it develops? Do antibiotics alleviate the lingering symptoms after the infection is cured? Two recent studies published in The New England Journal of Medicine shed light on these two controversial questions.

In the first study, conducted in Westchester County, New York, an area with high rates of Lyme disease, researchers gave a single dose of either an antibiotic or a placebo to patients who were bitten by deer ticks in the previous 72 hours.

The researchers found the antibiotic doxycycline prevented the disease form developing. However, only 3.2% of the untreated patients developed the characteristic bull's eye rash around the tick bite. This suggests the risk of Lyme disease is low even in Westchester County. The study also found the infection was more likely to develop from bites by ticks in the nymph stage, and if the tick was attached for 72 hours or more.

This study suggests preventive treatment is only worthwhile in areas with a particularly high incidence of the disease or if you are bitten by a nymphal deer tick that has been attached for three days or more. You should save the tick in a jar of alcohol so it may be identified to help you and your physician make that decision.

In the second study, researchers investigated whether prolonged treatment with antibiotics reduces the fatigue, muscle and joint pain, and mood or memory disturbances that some people experience even after the infection has cleared. But the study was discontinued early when preliminary results showed prolonged antibiotic treatment was no more effective than a placebo at improving the persistent symptoms.

If you are experiencing post-Lyme disease symptoms, long-term use of antibiotics is unlikely to help. But there is hope your condition will improve — the study found symptoms improved in 36% of the untreated patients.
September 2001 Update

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Flu Vaccine and Recurrent Heart Attack Risk

Late each fall, the call goes out to remind people to get their flu vaccinations. Most healthy people equate the flu with a week of being miserable. However for the elderly or people with chronic illnesses, the complications of influenza, such as pneumonia, can be life threatening. Good enough reason to get the shot, but now research suggests the vaccination may also lower heart attack risk.

The study, conducted by researchers at the University of Texas-Houston, questioned whether getting a flu shot could reduce the risk of a second heart attack in people with coronary artery disease. Scientists have been studying a potential link between cardiovascular disease and infection, and some of their work suggests upper respiratory infections, such as the flu, might be a risk factor for heart attack.

The investigators evaluated 218 individuals with previous heart attacks who were seen in the university's cardiology outpatient clinic during the 1997-98 flu season. Of the patients who met the study criteria, 109 experienced a heart attack during the study period. These volunteers were matched with 109 controls with coronary artery disease, but had not experienced a second heart attack during the same period.

Of those who had had new myocardial infarctions, the rate of flu vaccination during the current season was 47%, versus 71% among those who did not have new heart attacks. After adjusting for differences between these groups, the researchers found the risk of heart attack was reduced by two-thirds among patients who had gotten a flu shot that season. This study showed no evidence that use of multivitamins or physical exercise changed risk for recurrent heart attack.

No one knows how flu vaccination might reduce a person's risk of heart attack. Perhaps exposure to the flu might cause atherosclerotic plaques to become less stable or the stress of this illness might dangerously increase the heart's workload for people with cardiovascular disease. Other theories include an increased tendency for blood clots during the flu or that the flu may contribute to poor blood vessel function. Whatever the cause and effect, people with coronary artery disease (and who are not allergic to the vaccine) should strongly consider getting a flu shot this season.
September 2001 Update

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The Benefits of Surgery for Ear Infection are Unclear

Every year thousands of young children undergo surgery to alleviate chronic middle ear infections (otitis media). The demand for these procedures is driven by the concern that persistent bouts of ear infection will cause hearing loss and long-term effects on their child's speech and language development. However, the benefits of surgery are unclear — even after two recent new studies.

The most common operation involves inserting tubes through the eardrums to drain fluid that collects in the middle ear. Whether or not prompt implementation of this surgery actually protects against the development of infection was the subject of the first study in which 6,350 children were checked regularly for ear infections. By the age of 3, 429 of them were diagnosed with chronic ear infections. About half received the surgery as soon as possible, while the others waited up to nine months. The researchers found the children who had the surgery promptly had fewer subsequent ear problems than those who waited. But there was no significant difference in their speech, language, cognition or psychosocial development as measured by standardized tests and parental assessments. In fact the mean scores for all of the children fell with the average range for that age.

The second study examined hospital discharge records for children in Ontario to determine whether removing adenoids and/or tonsils at the same time as the insertion of tubes helped reduce the likelihood of subsequent ear problems. Of the 37,316 cases who received tubes, 28% also involved the removal of adenoids and/or tonsils. About one quarter of those who didn't undergo adjuvant surgery were re- hospitalized within two years after their initial surgery for subsequent ear problems. But those who did nearly halved their risk of re-hospitalization. Having both adenoids and tonsils out provided additional benefit.

So should children with chronic ear infections have tubes inserted, and should they also have their adenoids and tonsils taken out? Because of limitations in these and previous studies, we still don't know. More research is needed to weigh the long-term risks of hypothetical development impairment verses the not fully understood risk of the different surgeries.
August 2001 Update

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Killing H. Pylori Helps Prevent Gastrointestinal Bleeding in Patients Taking Low-Dose Aspirin

Many people take low-dose aspirin on a daily basis to help prevent heart attacks. Others take larger doses of stronger nonsteroidal antiinflammatory drugs (NSAIDs), such as naproxen (Anaprox, Aleve, others), to relieve musculoskeletal pain such as that caused by arthritis. When taken on a regular basis, however, NSAIDs often cause ulcers and gastrointestinal (GI) bleeding. Ulcers, which are raw, crater-like breaks in the mucosal lining of the digestive tract, may also be caused by excess acid production and a bacterium known as Helicobacter pylori (H. pylori).

In a study published in the New England Journal of Medicine, researchers enrolled 400 patients with a history of GI bleeding who were taking aspirin or other NSAIDs to prevent heart disease or to control musculoskeletal pain. They set out to find whether eradicating H. pylori infection reduces the risk of recurrent GI bleeding in these patients. For six months, 250 patients were given an 80 mg "baby" aspirin once per day, while the remaining 150 patients received 500 mg of naproxen twice per day. Within each of the two groups, patients were randomly assigned to take either a daily dose of omeprazole (Prilosec), an acid-suppressing medication, or a one-week antibiotic treatment to eradicate H. pylori infection, followed by placebo for the remainder of the trial.

The researchers found that in patients taking aspirin, those who were treated for H. pylori had a 1.9% risk of GI bleeding while the risk for those taking omeprazole was 0.9%. In other words, for patients on low-dose aspirin, the treatments were almost equal.

The results were very different for patients taking naproxen. 19% of the naproxen patients who had H. pylori treatment suffered from recurrent bleeding. In contrast, only 4% of the omeprazole group did.

The study suggests that patients with a history of GI bleeding who take low-dose aspirin to prevent heart attacks should be tested for H. pylori infection and treated if the infection is found to be present. Patients taking non-aspirin NSAIDs and who have experienced GI bleeding are more likely to benefit from acid-suppressing therapy.
April 2001 Update

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Warfarin and Vaginal Cream Drug Interaction Warning

The Food and Drug Administration (FDA) has issued a warning stating that women taking the prescription blood thinner warfarin (Coumadin) should consult their doctor or pharmacist before using over-the-counter vaginal creams containing the antifungal drug miconazole because of an increased risk of bleeding or bruising. Miconazole is an active ingredient in many over-the-counter creams and suppositories used to treat vaginal yeast infections.

Doctors were already aware of adverse reactions between warfarin and systemically administered miconazole. This warning urges women to beware of creams and suppositories as well.

The warning was issued in response to two reports of abnormal blood clotting tests in women taking the anticoagulant warfarin who used vaginal miconazole. In addition to the abnormal blood-clotting test, one of the two women also developed bruises, bleeding gums, and a nosebleed. Two journal articles also warned of a possible interaction between warfarin and vaginal miconazole.

The FDA warning will appear on miconazole-containing product labels and consumer brochures.
April 2001 Update

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Pneumonia: How Long Before You Feel Better?

Pneumonia is a serious infection or inflammation of the lungs. Uncomplicated pneumonia may be successfully treated with antibiotics in one or two weeks, but many patients continue to experience the symptoms of pneumonia, including cough, chest pain, fatigue, shortness of breath, and fever, for some time after that. A team of Canadian researchers set out to determine how long after treatment it should take for pneumonia patients to be symptom-free.

The scientists asked a group of 535 adults who had undergone a course of antibiotic treatment for pneumonia to complete questionnaires about persisting symptoms at two and six weeks after the completion of their treatment.

The average age of these patients was 62 years. Fifty-four percent of the patients were admitted to the hospital for treatment of their pneumonia, and a minority had a coexisting chronic illness such as chronic obstructive pulmonary disease, asthma, or congestive heart failure.

At two weeks after therapy, 67% of patients reported fatigue, 56% were coughing, 50% were short of breath, and 35% were producing sputum. Six weeks after therapy, more than 60% of patients reported continuing symptoms. Forty-five percent still had fatigue, 35% continued to cough, and 16% had gastrointestinal symptoms. Older patients, those who were sickest at onset of treatment, patients with chronic obstructive pulmonary disease, and patients with asthma suffered the most persistent symptoms.

Although hospitalizations are shorter and antibiotic treatments briefer, complete recovery still takes time. Pneumonia patients should be reassured that a "normal" period of recuperation may vary from several weeks to several months.
March 2001 Update

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Good News for Breast-Fed Babies

Breast-feeding has been linked to many advantages, including fewer earaches, colds, and asthma attacks. Now, a large trial involving almost 16,500 mother-infant pairs has shown even more benefits of breast-feeding. The study demonstrated that long-term, exclusive breast-feeding significantly decreases the risk of gastrointestinal tract infections and atopic eczema during a child’s first year of life.

Published in the Journal of the American Medical Association, the study involved mothers from the former Soviet republic of Belarus. To avoid a conflict of interest, given the advantages of breast-feeding that are already established, the program studied mothers who breast fed for a long time compared to mothers who breast fed for a short time then switched to bottle feeding. Some hospitals were randomly chosen to promote breast- feeding, through programs involving counseling from doctors and midwives; other hospitals, which served as a control group, provided the usual obstetric care. After 12 months, nearly 20% of the infants who were part of the breast-feeding program were still nursing, compared to 11.4% of the control group.

In the first year, only 9% of the infants in the breast-feeding program had one or more gastrointestinal infection compared to about 13% of the control group. In addition, 3% of the breast-fed infants developed atopic eczema (a scaly, allergy-associated skin irritation), compared with 6% of the other babies.

The World Health Organization recommends only breast milk for the first four to six months, and recommends that breast-feeding (in combination with formula) continue until 2 years of age. The American Academy of Pediatrics recommends breast milk alone until 6 months, and breast-feeding plus formula until 12 months old. This study suggests that breast-feeding exclusively for the first year could provide greater health benefits to the child.
February 2001 Update

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Meningococcal Disease Prevention for College Students

Meningococcal disease is an inflammation of the membranes that encase and protect the brain and spinal cord. When caused by a bacterial infection, meningococcal disease can be fatal. Survivors can suffer significant lifelong impairments, including permanent brain damage or hearing loss.

In recent years, the incidence of meningococcal disease has been on the rise in 15- to 24-year-olds in the United States. And the Centers for Disease Control and Prevention (CDC) has revealed that U.S. college students living in a dormitory setting are more than three times as likely to contract meningococcal disease than those in the same age group who do not live in a dormitory setting. Freshmen face the greatest risk.

Sixty percent or more of these cases could be prevented with an existing, available vaccine. Adverse reactions to the vaccine have been shown to be mild, and serious reactions are rare. Based on findings from recent studies and on input from expert committees, the American Academy of Pediatrics advises physicians to inform college-bound patients who intend to live in a dormitory of the increased risk for meningococcal disease and of the benefits and limitations of the vaccine. Physicians are also advised to make the vaccine available to those patients who then request it.

U.S. military recruits have been routinely vaccinated against meningococcal disease since 1971, in response to a high incidence of the disease in that population.
February 2001 Update

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Treating Chronic Hepatitis C

An estimated 3.9 million people in the United States are infected with the hepatitis C virus (HCV). Hepatitis C affects the liver. In many — but not all — cases, hepatitis C progresses from mild to moderate inflammation (hepatitis), to scarring (fibrosis), to severe fibrosis with loss of liver function (cirrhosis), and finally liver failure. It is the leading cause of chronic liver disease and liver transplantation. But not all cases of hepatitis C progress to cirrhosis and the rate of progression of the disease is often unpredictable.

The standard of care for treating hepatitis C is a combination of the antiviral drugs interferon-alpha and ribavirin. However, these drugs are not completely effective, they cause side effects, and they are expensive. Given the drugs' limitations and the unpredictable nature of disease progression, doctors remain in disagreement about whether treatment should begin at the onset of mild inflammation, or whether it should be delayed until a moderate amount of inflammation or cirrhosis exists.

Using information from recent studies about the natural progression of HCV, researchers created a computer model that would help determine the optimal time to start combination antiviral drug therapy with interferon-alpha and ribavirin. The simulation projected that 18 percent of patients who had a liver biopsy every three years and started treatment at the onset of moderate inflammation would progress to cirrhosis after 20 years. This strategy avoided the need for treatment in 50 percent of patients, and increased life expectancy by 1.2 years. In patients who began treatment at the onset of mild inflammation, only 16 percent would progress to cirrhosis after 20 years, increasing life expectancy by another 0.4 years. In comparison, the computer model predicted that 27 percent of patients in the control group, which was left untreated, would have cirrhosis after 20 years.

This study illustrated that beginning antiviral treatment at the onset of mild inflammation is the most effective treatment strategy. However, for patients with HCV and mild inflammation of the liver who do not wish to receive drug treatment or hope to delay it, biopsy management is also a reasonably effective option that could avoid treatment altogether.

A Promising New Drug: Peginterferon
In January 2001, the FDA approved Peg-Intron (peginterferon) to treat hepatitis C. Peginterferon is a form of interferon-alpha that stays active in the immune system longer than interferon-alpha. As a result, it can be taken once a week, as opposed to three times a week.

Two recent studies published in the New England Journal of Medicine compared the effects of another brand of peginterferon, called Pegasys, with interferon-alpha on patients with chronic hepatitis C. Both studies revealed that peginterferon is significantly more effective in managing the virus. It was also better tolerated and had fewer side effects.

In the clinic, interferon-alpha is usually given in combination with ribavirin, which has been shown to double the effectiveness of interferon-alpha. Researchers regard testing a combination of peginterferon and ribavirin the next logical step in determining how to treat this disease more successfully.
February 2001 Update

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Zinc Lozenges Have No Beneficial Effect on the Common Cold

Over the past few years, more and more people have begun to reach for zinc lozenges at the first sign of a cold. But a study published in the journal Clinical Infectious Diseases suggests that there is little scientific evidence of zinc's effectiveness to support the treatment's popularity.

In a study funded by Warner Lambert Consumer Healthcare, a company that manufactures zinc lozenges, researchers conducted two clinical trials to test zinc's efficacy. One trial involved 273 people who were exposed to a specific cold virus, called rhinovirus, to induce a cold. The other trial involved 281 subjects with natural colds. Both groups were broken up into four subgroups that received one of the following treatments: 13.3 milligrams (mg) of zinc gluconate, 11.5 mg of zinc acetate, 5 mg of zinc acetate, or a placebo. Zinc gluconate and zinc acetate are different formulations of zinc; zinc gluconate is more commonly found in lozenges. Treatment was started within a day of the onset of cold symptoms and continued every 2-3 hours (up to 6 lozenges per day) until the cold symptoms disappeared, or up to 14 days.

The researchers measured the effects of the treatments on both the duration and severity of the colds. Patients self-scored the severity of seven cold symptoms: sneezing, runny nose, nasal obstruction, sore throat, cough, headache, and hoarseness.

At the end of the study, researchers found that zinc gluconate had a small but significant effect on the duration of induced cold symptoms. People who had taken zinc gluconate had cold symptoms for about 2.5 days as opposed to 3.25 for high-dose zinc acetate and 3.5 days for low-dose zinc acetate and placebo. None of the treatments, including zinc gluconate, reduced the severity of cold symptoms for the first three days of the cold. And none of the zinc preparations or placebo had a significant effect on the duration or severity of symptoms in people with natural colds.

Overall, the study suggests that zinc lozenges have little, if any, beneficial effect on the treatment of the common cold.
January 2001 update

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Pet Reptiles and Salmonella

Between 1996 and 1998, approximately 16 state health departments reported salmonella infections in persons who had direct or indirect contact with reptiles (i.e., lizards, snakes, or turtles) to the Centers for Disease Control and Prevention.

Salmonella infection can result in severe illness and even death, particularly in infants, young children, and anyone with a compromised immune system. The CDC issued the following recommendations to reduce the chances of anyone in your family contracting this potentially deadly infection from these increasingly popular exotic pets:

  • Pet store owners, veterinarians, and pediatricians should provide information to owners and potential purchasers of reptiles about the risk of acquiring salmonellosis from reptiles.
  • People should always wash their hands thoroughly with soap and water after handling reptiles or reptile cages.
  • People at increased risk for infection or serious complications of salmonellosis (e.g., children younger than age 5 and immunocompromised persons) should avoid contact with reptiles.
  • Pet reptiles should be kept out of households where children younger than age 5 and immunocompromised persons live. Families expecting a new child should remove the pet reptile from the home before the infant arrives.
  • Pet reptiles should not be kept in childcare centers.
  • Pet reptiles should not be allowed to roam freely throughout the home or living area.
  • Pet reptiles should be kept out of kitchens and other food-preparation areas to prevent contamination.
  • Kitchen sinks should not be used to bathe reptiles or to wash their dishes, cages, or aquariums. If bathtubs are used for these purposes, they should be cleaned thoroughly and disinfected with bleach.

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Symptomless Genital Herpes Infections

Recent research tested a potential vaccine against genital herpes only to find it ineffective. But study investigators did learn something very important about this infection. During the course of the trial, 63% of study volunteers who developed antibodies to the virus (indicating exposure) never developed symptoms. Women were about equally likely to develop symptoms or not.

Perhaps the most important message here is that while a newly acquired genital herpes infection may cause no symptoms, new symptoms of genital herpes may in fact result from an old infection. If you or your sexual partner develop symptoms of genital herpes, it is very possible that this is ancient history coming to light in the context of a new relationship.

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Lyme Disease Vaccine

Should you get the Lyme disease vaccine? Experience so far has shown that the vaccine, which is called LYMErix, is safe and effective. The side effects include a couple of days of soreness in the upper arm where the vaccine was injected, short-term headache, and flu-like symptoms. The largest study of the vaccine, published in the July 23, 1998, New England Journal of Medicine and the basis for its FDA approval, showed no difference in long-term, arthritis-like side effects between the treatment group and the placebo group. That finding reassures those concerned that the vaccine might provoke an autoimmune response (when a person’s immune system attacks his or her own body). The same clinical trial showed that when the full, three-shot series of the vaccine was given, it was 76% effective — that is, the people who received all three shots were 76% less likely to come down with Lyme disease than people who received three placebo shots. As with other vaccines, however, its effectiveness is probably lower among older people because as the immune system ages, it gets less responsive.

But just because it is safe and it works doesn’t mean it’s necessary. Lyme disease is transmitted by deer ticks infected with the Borrelia burgdorferi bacteria. Your risk of getting Lyme disease comes down to primarily three factors: the number of infected deer ticks in the environment; what you do in that environment; and how much of an effort you make to keep ticks off you in the first place and remove them if they do bite you.

Infected deer tick territory is concentrated in southern New England, New York, New Jersey, Pennsylvania, Maryland, and a few counties of Minnesota and northeastern Wisconsin. Even in these hotbeds, only 15–30% of ticks are infected with the disease-causing bacteria. Also, the number of ticks is very sensitive to local conditions and can vary tremendously from town to town or even from block to block. Deer ticks favor moist, bushy, leafy places — not the wide expanse of your lawn, the beach, or even grass-covered dunes. Do you need to get the Lyme disease vaccine if you’re going to Martha’s Vineyard this summer to swim, play and lounge on the beach, and shop? Probably not. But if you plan on clearing brush and doing some gardening in a high-risk area, you might be a good candidate for the Lyme disease vaccine. Even then, some doctors question whether the vaccine is warranted, partly due to lingering doubts about how long protection lasts. Booster shots may be necessary. Also, deer ticks carry other diseases that the vaccine does not protect against. People who garden in tick-infested areas can (and should) take other precautions, like wearing high rubber boots. Hikers and birdwatchers can cut down on their risk by sticking to the center of well-traveled paths.

The time of year also makes a big difference. Lyme disease season starts around May on the East Coast and in the Upper Midwest. It continues through June and July when the deer ticks are in their nymphal stage. It is not so much that these nymphs are super-infectious. Rather, they are so small that people can’t spot them easily — especially because these tiny pests favor hard-to-spot places on the body. By August, most of these young ticks have either died or satisfied their appetite. Adult ticks are still active and infected, but their size (about that of an apple seed) makes them easier to see.

About 12,500 cases of Lyme disease are reported to health authorities every year, and many more go unreported. Because they play outside, children are vulnerable, and approval of a child version of LYMErix could come later. No one questions the value of the vaccine, but it isn’t for everyone — even where infection rates are relatively high.

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Starve a Cold, Feed a Fever, Take a Pill for the Flu?

The height of the flu season is starting to wane, but we seem to be at the peak of print and television ads promoting new treatments. Late in 1999, the U.S. Food and Drug Administration approved two new anti-influenzal drugs zanamivir (Relenza) and oseltamivir (Tamiflu). Both work by interfering with an enzyme needed for the flu virus to reproduce. Both offer an option for treating uncomplicated cases of the flu.

In clinical trials, when taken within two days of the onset of flu symptoms, Relenza was shown to make people feel better a little (about 36 hours) sooner. This drug is administered in an inhaler twice daily for five days. Relenza has not been proved effective for people who have severe asthma or chronic breathing problems, and in fact may cause bronchial spasms in these individuals. Tamiflu comes in pill form (taken twice a day for five days) and can reduce the length and severity of flu symptoms if it is taken within two days of the onset of symptoms, but not by much.

Patients participating in two clinical trials reported feeling better about one day sooner than patients taking a placebo. The most common side effects of Tamiflu included upset stomach, vomiting, trouble sleeping, and dizziness. Neither drug can prevent people from passing the flu on to others. These medications may offer some relief to flu sufferers, but getting a flu vaccine remains the best way to minimize your chances of getting this virus in the first place. This is true for healthy people and especially for people at high risk for complications from the flu (the elderly and people with compromised immune systems or chronic lung diseases).

In fact, the safety and effectiveness of these new flu treatments are unproven in these populations. What's more, Tamiflu and Relenza are effective only against influenza types A and B, but not type C (a very common, less severe flu) and many upper respiratory infections caught during the winter are viral, and not the flu.

The bottom line is that these medications are helpful in only a handful of situations. An extra day of fluids and bed rest may be all you can do.

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A New Approach to Testing for Cervical Cancer

Most women know that regular Pap smears can almost eliminate the chances of developing invasive cervical cancer. By examining the cervix for abnormal (and potentially precancerous) cells, treatment can be started before a real problem develops.

What many women may not know is that human papilloma viruses (HPVs) (which cause genital warts) are responsible for the majority of cases of cervical cancer. Two recent studies suggest that regular screening for HPV may prove even more effective than the traditional Pap smear in preventing cervical cancer.

The first study included 8,554 women who lived in the Gaunacaste Province of Costa Rica, where there is a very high rate of cervical cancer. Researchers found that HPV testing picked up 17% more high-grade cervical cell abormalities and cancers.

The second study compared the Pap smear with testing vaginal samples for HPV. 1,415 women in South Africa (who had not had any cervical cancer screening) participated. The first HPV test was done by a doctor during a routine physical exam. The HPV test was done on samples of vaginal fluid the women collected themselves using a cotton swab. All the women had Pap smears done as well. The HPV testing on samples taken by the doctor detected far more cervical disease than the Pap smear (84% vs. 68%). The HPV testing done on the self-collected samples was not equivalent to the HPV tests done on the physician-collected samples, but was just as good as the Pap smear. And did not require a trip to the doctor’s office.

What are the important take-home messages from these studies? First, each year in the United States there are an estimated 15,000 new cases of cervical cancer. Each year, about 5,000 women will die needlessly of the disease. Regular Pap smears are the most effective way to screen for this disease. Second, although HPV is one of the most common sexually transmitted infections, only a small number of women suffer complications, including cervical disease. There are over 70 types of HPV, but only 13 are known to cause cervical cancer.

Still, screening techniques that include HPV testing may not only increase the ability to detect abnormal cell changes early, but can also let a woman know whether or not she carries one of the more dangerous viruses (and therefore needs to be extra vigilant about screening). Finally, self-collected samples for testing may take us a big step forward in preventing this disease in places where women do not get regular visits to the doctor.

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New Pneumococcal Vaccine for Children Less Than Two Years Old

A new vaccine called Prevnar is the first vaccine to protect children less than two years old against the bacteria Streptococcus pneumoniae, which is the leading cause of pneumonia, bacterial meningitis, bacteremia, sinusitis, and acute otitis media, or middle-ear infections, in young children. In addition to protecting children from pneumococcal infection, vaccination with Prevnar also decreases transmission of pneumococci from one child to another, an effect known as "herd immunity." Furthermore, since middle-ear infections are the leading reason that children need to take antibiotics, vaccination with Prevnar could reduce the need for antibiotics in this age group. This, in turn, should slow or reverse the trend of antimicrobial resistance. A different pneumococcal vaccine, known generically as PPV23, has been available to adults for years, but it has not been effective in children less than two years old.

The Centers for Disease Control and Prevention's (CDC's) Advisory Committee on Immunization Practices (ACIP) recommends that all children less than two years old should be vaccinated with Prevnar. Children aged two to five years old should receive a two-shot series of Prevnar followed by one dose of PPV23 if they are high-risk, a category that includes children with HIV, immunocompromising conditions, chronic illness, or sickle cell disease. Prevnar may also be considered for children between two to five years with priority given to those who are between the ages of 24 and 35 months, of African-American, American Indian, or Alaska Native descent, or who attend group day care centers.

Since Prevnar has not been studied sufficiently in children older than five years who are at high risk for serious pneumococcal disease, ACIP continues to recommend that children five and older receive PPV23.

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Tamiflu (Oseltamivir) for Flu Prevention

Until recently, there wasn’t much a person could do once he or she was hit with the flu. However, the Food and Drug Administration approved two medications that could be added to the usual routine of fluids, bedrest, and fever-reducing analgesics. Both drugs interfere with an enzyme (neuraminidase) that is crucial for the flu virus to multiply. Taken within two days of symptom onset, zanamivir (Relenza) and oseltamivir (Tamiflu) can reduce the severity and duration of a bout with this winter menace. Now, the FDA has also approved Tamiflu for the prevention of influenza in adults and children 13 and older.

The FDA’s approval was based on several recent studies. One trial followed healthy, unvaccinated adults and adolescents who took 75 mg of Tamiflu or a placebo once a day for 42 days during a community outbreak of the flu. The flu rate among study subjects taking the placebo was 4.8%, while only 1.2% of the Tamiflu group came down with the virus. In a second study, researchers assigned elderly nursing home residents to either a placebo or 75 mg of Tamiflu daily for 42 days. Of the placebo group, 4.4% developed the flu, compared with only 0.4% of the treatment group. (It is important to note that in this study, 80% of the elderly population had gotten a flu shot.) A third investigation evaluated whether Tamiflu could prevent the spread of the virus within a household. Family members received either 75 mg of Tamiflu or a placebo within two days of the onset of symptoms in the flu sufferer. In placebo households, the flu rate was 12%. In the Tamiflu households, only 1%.

Note that Tamiflu is not a substitute for the flu shot and those at high risk for complications of the flu should get their yearly vaccination. None of these studies tested Relenza (zanamivir), so it is unclear whether this drug offers similar benefits. Keep in mind, both Tamiflu and Relenza are effective only against type A and type B flu viruses, and although many upper respiratory infections and severe colds caught during the winter are viral, that doesn’t mean they are "the flu."

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©2000–2006 President & Fellows of Harvard College

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