Delaying Vaccines Risks Serious Infection
▸ Varicella. It's a widespread misconception that varicella is serious only in adults. In fact, prior to the licensure of the vaccine, the case-fatality rate from pneumonia, encephalitis, and secondary bacterial sepsis among children less than 1 year of age with chicken pox was 7 times higher than that of those aged 1-10 years, at 6.23 versus 0.75 cases per 100,000 children (MMWR 1996;45[RR-11]:1-36). During the 1990's, the combination of varicella and group A streptococcus was a deadly one, often leading to extensive necrotizing infection or sepsis, hospitalization, and death. Currently, there is concern that methicillin-resistant Staphylococcus aureus (MRSA) also may be an opportunistic pathogen any time there is a break in the skin.
According to the alternative schedule, it's okay to delay varicella vaccine until 18 months; the selective schedule advises waiting until the child is 10 years old, ordering antibody titers, and immunizing only if the child is found susceptible. Clearly, these approaches do not provide early protection from disease. Fortunately, there is little wild-type varicella currently circulating in the community, and the cases that do break through in vaccinated children are usually mild, with small numbers of lesions. However, if immunization rates fall and wild-type varicella becomes more common, more cases complicated by MRSA are likely to occur.
That is one reason why I am particularly concerned with the recent trend of parents organizing “chicken pox parties” to deliberately expose their children to varicella, under the mistaken belief that this is a good way to achieve protection without immunization.
Because there is still no chicken pox vaccine available for children less than 1 year of age, the only way to prevent disease in this high-risk group is to prevent exposure by immunizing their siblings, day care contacts, babysitters, and anyone else with whom they come into regular contact. Not only do the chicken pox parties demonstrate a lack of understanding of the potential seriousness of varicella, but they completely ignore the potential for secondary cases within a household in susceptible adults or infants. Please do your best to educate parents in your practice about the risks of wild-type varicella in young infants and the potential for MRSA suprainfection.
While delaying immunization may make some people feel good, it leaves the most vulnerable of our patients at great risk. It will take time to explain to parents that the currently recommended vaccine schedule incorporates our knowledge about age-related susceptibility, morbidity, and mortality. Delay is not in their child's interest.
