For many adults, vaccinations are kids' stuff. Indeed, most immunizations are designed for children, and most new vaccines are headed for pediatric offices. But infections strike people of all ages, and immunizations are important for adults, too.
Aside from travelers and people with special needs and vulnerabilities, healthy adults have had only three vaccines to keep track of: For everyone over 50, a flu shot every fall; for everyone at age 65, a pneumococcal pneumonia shot; and for all of us, a tetanus-diphtheria (Td) booster every 10 years. But two new vaccines have joined the list.
A vaccine for shingles
The culprit is varicella-zoster virus (VZV), the same virus that causes chickenpox (varicella in children). The vast majority of children recover completely, but that's not the end of the story. Instead of being killed and eliminated from the body, VZV goes into hibernation, hiding out in the part of the nervous system known as the sensory nerve ganglia. In most people, the virus remains dormant for life, but in up to 15%, VZV becomes active and causes shingles.
Most patients with shingles are older than 60, and some have weakened immune systems. The virus spreads along the sensory nerve to form a line of blisters on one side of the body. Most patients recover fully, but a few develop serious complications, and up to a third develop long-lasting pain (post-herpetic neuralgia).
Ninety percent of American adults had chickenpox as children, and all of them are at risk for shingles. Enter the new vaccine. It is similar to the pediatric varicella vaccine, but it contains a much larger dose of the weakened VZV virus than the chickenpox vaccine does.
The new vaccine, Zostavax, is suggested for people age 60 and older but should not be given to those who have immune systems that have been weakened. Doctors don't yet know how long the vaccine's protection will last or if booster shots will be needed.
A booster for whooping cough
Every American infant should get a series of immunizations against tetanus and diphtheria. But in addition, the childhood vaccine has a third component to protect against pertussis, or whooping cough. For decades that meant a DTP shot; now it's known as DTaP, since the improved whooping cough component is made from an acellular (a) pertussis (P) vaccine.
The adult Td booster lacked a because, unlike tetanus and diphtheria, whooping cough is a childhood illness — or at least it used to be. In recent years, whooping cough has been on the rise. Whooping cough in adults and adolescents is subtle. As in youngsters, it often begins with a runny nose and a low-grade fever. Then the cough starts — and typically continues for 2 weeks to 2 months. Most often, the cough is dry, and fever is mild or absent. The cough can be debilitating. Most patients recover fully, even without antibiotics, but they can pass the infection to others in the meantime.
Whooping cough is making a comeback because the childhood vaccine's protection wanes over time. Immunity to tetanus and diphtheria also wears off, which is why doctors advise a booster every 10 years. But until now, boosters for adolescents and adults lacked the because older people were likely to develop fever and other reactions. Fortunately, the new acellular pertussis vaccine is much better tolerated.
Two brands of the new vaccine are available. Boostrix is licensed for use in 10- to 18-year-olds, and Adacel is approved for ages 11–64. Adolescents should get a Tdap booster 5 years after their last Td shot; adults should get it 10 years after their last Td booster. Tdap is not approved during pregnancy or after age 65, but studies are underway to see if it's safe in these circumstances.
More to come
It takes years to bring a vaccine from the lab to FDA approval, but in addition to the vaccines for shingles and whooping cough, the FDA has approved Gardasil, a vaccine that protects women against the strains of human papilloma virus that cause most cases of cancer of the cervix. To learn more about Gardasil, please see the September 2006 HMS Family Health Guide update, "The cervical cancer vaccine."
November 2006 Update