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December
2000
Tamiflu
(Oseltamivir) for Flu Prevention
Until recently,
there wasn’t much a person could do once he or she was hit
with the flu. Last year, 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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Wet
Combing More Effective for Detecting Head Lice than Traditional
Visual Inspection
Head lice are minute, parasitic insects that live in hair. They
easily spread from person to person, especially among children
at school or in day care, and they are responsible for many school
absences. Because lice are barely visible, finding lice eggs,
called nits, is the easier way to detect an infestation. These
tiny, white flecks cling to hair shafts. Researchers at Belgium’s
Ghent University recently found that carefully sweeping a fine-toothed
comb through wet, conditioned hair is more effective for detecting
lice than the traditional, dry-scalp visual inspection.
The study, published in the British Medical Journal, compared
the two methods on 224 school children. Two trained teams independently
examined the students; one using the wet comb technique, the
other using the visual test. Wet combing found lice in 49 children,
while the visual test only detected 32 of these cases. In addition,
the traditional inspection mistakenly identified 14 uninfected
children as having lice.
The results suggest that compared to traditional, visual inspection,
wet combing would allow for more accurate head lice detection,
meaning more infestations detected before they can spread, and
fewer non-infested children receiving unnecessary treatment with
insecticides.
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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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Early
versus Later Orthodontic Treatment in Children
Which approach works best for children who need orthodontic care:
early two-phase treatment (which begins when a child still has
all or most of his or her "baby" teeth) or later single-phase
treatment (which is implemented when most, or all, of the permanent
teeth are in)? Proponents of early two-phase orthodontic treatment
argue that it is better able to modify the patient's skeletal
growth, improve the patient's self-esteem. They also believe
this approach achieves a better and more stable result and reduces
the need for extensive therapy later. A University of North Carolina
study, however, reports early two-phase orthodontic treatment
is not necessarily superior to later single-phase treatment,
nor does it always achieve all the goals some orthodontists claim
it does.
Most people do not have perfect teeth, however, malocclusion
is a condition where the jaws are misaligned. In very severe
forms of malocclusion, the misalignment may interfere with the
ability to speak or eat. The children in the North Carolina trial
did not have such extreme misalignment. These children were determined
to have moderate-to-severe Class II malocclusion. Children with
a Class II malocclusion have some jaw misalignment. In addition,
teeth may be crowded, abnormally spaced, or misaligned. This
type of malocclusion can also involve upper teeth that protrude
excessively or front teeth that do not meet. Malocclusion usually
becomes apparent between ages 6 and 14, when the teeth and jaw
are growing and often runs in families.
In this study, researchers randomly assigned children who still
had most of their baby teeth to one of three groups: headgear
treatment (fixed-appliance therapy), bionator therapy (removable-appliance
therapy), or to an observational group that received no treatment.
Seventy-five percent of the children in both the headgear and
bionator therapy groups showed improvement in jaw alignment (although
there was significant variation across all three groups).
The second phase of the study was to see whether the improvements
achieved in the first phase of the study truly represented long-term
results. Once the children's permanent teeth came in, study investigators
randomly assigned members of all three groups to receive fixed-appliance
therapy. Researchers discovered that the skeletal changes resulting
from early treatment did not last. In addition, skeletal relationships,
as well as the relationship between the upper and lower jaws,
did not differ significantly between the groups that received
the early two-phase treatment and the group that received later
single-phase treatment. Neither the length of treatment nor the
severity of the malocclusion was an important influence on the
end result. Individual skeletal growth patterns, however, did
play an important role.
One of the conclusions from this study is that the success of
Class II correction does not depend on when treatment begins
as long as it begins while the child is still growing. If the
criterion for success of Class II correction is a better, more
stable result, the later single-phase treatment would be preferable
because treatment time is shorter. However, if the criteria for
success include better self-esteem, then it may be preferable
to start treatment earlier. It is important to keep in mind that
early treatment is not the only way to correct malocclusion.
A Class II correction can be achieved early or later with equally
beneficial results. Other studies have been conducted that support
these findings among children with more severe occlusions and
other orthodontic problems.
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Study
Links Smoking to Colorectal Cancer
Lung, mouth, and bladder cancers, among others, are well
established as cancers caused by cigarette smoking. A recent
study from the American Cancer Society, published in the Journal
of the National Cancer Institute shows that cigarette
smoking also raises the risk of dying from colorectal cancer,
which is cancer of the colon or rectum. Indeed, the study
notes that as many as 12% of colorectal cancer deaths in
the United States may be associated with smoking.
Researchers analyzed data from 312,332 men and 469,019 women
enrolled in the Cancer Prevention Study II. They found that
for both men and women, risk of colorectal cancer increased
after 20 or more years of smoking. Among men, current smokers
were 31% more likely to die from colorectal cancer than nonsmokers;
female smokers were 41% more likely than nonsmokers to die
from the disease. The risk of death from colorectal cancer
rose with the number of years cigarettes were smoked, the
number of cigarettes smoked per day, and the number of packs
smoked over the years. In addition, the risk of death was
higher the younger a person was when he or she started smoking.
The association was not confined to cigarette smoke. Those
who smoked pipes or cigars also faced a significantly increased
risk of death from colorectal cancer.
The bright spot of the study was that it showed a benefit
from quitting. Twenty years after quitting, men's risk of
colorectal cancer death returned to normal. And women who
had stopped smoking 10 or more years earlier had the same
risk as nonsmokers. The take-home message: If you smoke,
stop. If you don't smoke, don't start.
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