Jan. 4, 2000 (Atlanta) -- Childhood vaccine recommendations for the U.S. in the year 2000 bring several major changes, but few surprises. The annual advisory is a joint effort of the American Academy of Pediatrics (AAP), the CDC's Advisory Committee on Immunization Practices (ACIP), and the American Academy of Family Physicians (AAFP).
"People should know that immunization ranks right up there with the greatest achievements of the 20th century," Michael Gerber, MD, FAAP, a member of the AAP committee on infectious diseases, tells WebMD. "We have eliminated smallpox, are on the verge of eliminating polio, and can eliminate measles and other killer diseases. Because of the success of vaccination, people no longer realize how awful whooping cough or Haemophilus influenzaemeningitis can be. People need to remember that the benefits far outweigh the risks of vaccination."
The 2000 immunization schedule has three major changes: it recommends complete replacement of oral poliovirus vaccine (OPV) with inactivated poliovirus vaccine (IPV); it advises routine childhood hepatitis A virus (HAV) vaccination in 11 states; and it advises continued suspension of rotavirus vaccination.
A bigger change may come later in the year when experts anticipate FDA approval of a pneumococcal vaccine capable of preventing a common cause of bacterial meningitis and pneumonia as well as bloodstream infections.
Roger Burr, MD, MPH, a medical epidemiologist at the CDC's National Immunization Program in Atlanta, tells WebMD that the most important difference this year is the change to an all-IPV schedule. The IPV contains an inactivated virus as opposed to a live virus.
ACIP chairman John F. Modlin, MD, agrees. "The change to inactivated vaccine is part of a natural progression of policy that has been taking place over the past several years," he tells WebMD. "We have had two vaccines. The oral vaccine is live, and can cause very rare cases of poliomyelitis. Because the threat of polio is diminishing on a worldwide basis, it is now considered prudent to use the inactivated vaccine."
From 1962 until the mid-1990s, the U.S. relied entirely on the oral poliovirus vaccine. Because this live vaccine replicates just like virulent polio, it could actually spread and extend vaccine coverage in areas where relatively few people actually received the vaccine -- a phenomenon called backdoor immunity.
"In communities where vaccine acceptance rates were very low, it was considered a real advantage," says Modlin, professor of pediatrics at Dartmouth Medical School in Hanover, N.H. "OPV was used for very valid public health reasons. But now the very small risk from IPV outweighs that benefit."
In 1997, the AAP/ACIP/AAFP recommended a change in policy to two doses of IPV followed by two doses of OPV. The Y2K recommendations thus represent further evolution of this change. Modlin says, "IPV confers excellent protection against polio. ... It's a judgement call [over which vaccine to use]; there aren't any strong data to help you one way or the other. But we haven't seen polio in this country for 20 years. I think it's a very good change."
The new recommendation for hepatitis A vaccination calls for the addition of two doses of the HAV vaccine to the routine schedule beginning at age 2 in states where risk of HAV infection is twice the national average. These states are Arizona, Alaska, Oregon, New Mexico, Utah, Washington, Oklahoma, South Dakota, Idaho, Nevada, and California.
The hepatitis B vaccine should not be confused with the hepatitis A vaccine. Hepatitis A is often acquired through contaminated water or food or from person-to-person contact; hepatitis B is acquired from exposure to blood and body fluids. The hepatitis B vaccine series begins at birth in all children throughout the U.S.
Continued suspension of the rotavirus vaccine is another change since the January 1999 recommendations were issued. The FDA in 1999 suspended approval of the vaccine after the CDC confirmed a link between receiving the vaccine and a rare form of bowel obstruction. Rotavirus causes a severe diarrheal disease in children, especially infants. An improved vaccine is needed to prevent this serious illness.
"It is possible that if we had continued with the rotavirus vaccine the benefits would have been more apparent," Modlin says. "But the risk of a serious complication, which we now know is very real, is estimated to occur in 1 in 5,000 recipients. It wasn't tenable to continue to take on that risk, even if in the very, very long run you might eventually prevent more cases of disease and death. We know what the risk is, but we can only estimate the benefits."
Another big change may come before the next annual recommendations: A pneumococcal vaccine is very close to FDA approval. "We are anticipating the availability of a new pneumococcal vaccine," Modlin tells WebMD. "We think there is a strong possibility that the FDA will license it very early in the new year." Burr, however, is skeptical that approval will come so soon. "Because of the way things work, I don't think the pneumococcal vaccine will come along real quickly," he says.
The following list represents an overview of the Y2K recommendations:
- Hepatitis B virus (HBV) vaccine: should be given from birth to age 2 months, a second dose at least 1 month after the first dose, and a third dose administered at least 4 months after the first dose and at least 2 months after the second dose. Unimmunized children may begin the series at any visit.
- Diphtheria/tetanus/acellular pertussis (DTaP) combination vaccine: should be given at ages 2 months, 4 months, 6 months, 15-18 months, and 4-6 years. Tetanus and diphtheria toxoids (Td) is recommended at 11-12 years of age. Td boosters are recommended every 10 years.
- Haemophilus influenzae type b (Hib) conjugate vaccine: combined vaccines should not be used for primary immunization in infants at 2, 4, or 6 months of age pending FDA approval. Hib vaccination is recommended at ages 2, 4, 6, and 12-15 months.
- Polio vaccine: oral polio vaccine no longer is recommended for routine use in the U.S. IPV should be given at 2 months, 4 months, 6-18 months, and 4-6 years of age.
- Measles/mumps/rubella (MMR) vaccine: should be given at ages 12-15 months and 4-6 years. Children not given the second dose should get it by age 11-12 years.
- Varicella vaccine: on or after the first birthday for children lacking a reliable history of chickenpox. Susceptible people 13 years of age or older should receive two doses at least 4 weeks apart.
- Hepatitis A vaccine: should be given to children 2 years of age or older in Arizona, Alaska, Oregon, New Mexico, Utah, Washington, Oklahoma, South Dakota, Idaho, Nevada, and California.