Rubella in the workplace: the need for employee immunization.

From 1983 to 1985, the New York City Department of Health investigated five workplace outbreaks of rubella. Approximately 40 per cent of the 265 cases were detected among women of child-bearing age (15-44 years). Data are reviewed from the 1983 Financial District outbreak to illustrate the continued susceptibility of young adults, the missed opportunities for rubella immunization, and the danger of congenital infection. A comprehensive rubella immunization program is required to protect pregnant women and eliminate congenital rubella. As one important component of this effort, employee health physicians are urged to assess the immune status of women of child-bearing age and to vaccinate all susceptibles who are not pregnant.

Measles outbreak in a vaccinated school population: epidemiology, chains of transmission and the role of vaccine failures.

An outbreak of measles occurred in a high school with a documented vaccination level of 98 per cent. Nineteen (70 per cent) of the cases were students who had histories of measles vaccination at 12 months of age or older and are therefore considered vaccine failures. Persons who were unimmunized or immunized at less than 12 months of age had substantially higher attack rates compared to those immunized on or after 12 months of age. Vaccine failures among apparently adequately vaccinated individuals were sources of infection for at least 48 per cent of the cases in the outbreak. There was no evidence to suggest that waning immunity was a contributing factor among the vaccine failures. Close contact with cases of measles in the high school, source or provider of vaccine, sharing common activities or classes with cases, and verification of the vaccination history were not significant risk factors in the outbreak. The outbreak subsided spontaneously after four generations of illness in the school and demonstrates that when measles is introduced in a highly vaccinated population, vaccine failures may play some role in transmission but that such transmission is not usually sustained.

Major impediments to measles elimination. The modern epidemiology of an ancient disease.

Great success has been achieved in controlling measles in the United States with a greater than 99% reduction in incidence rate from the prevaccine era. However, since 1981, the incidence rate of measles in the United States has been relatively stable at approximately 1,500 to 3,000 reported cases annually. We reviewed available information to determine the remaining impediments to elimination of measles. The potential impediments can be divided into two categories: (1) implementation of the current strategy and (2) whether the current strategy needs modification. The major reason for the failure to achieve elimination appears to be the fact that some persons for whom vaccine is indicated have not been vaccinated. While vaccine failures and importations play a role in transmission, sustained transmission in a totally vaccinated community has not been demonstrated. All chains of transmission have involved some unvaccinated persons. Measles elimination will require complete implementation of current strategies and careful monitoring of epidemiologic trends to determine whether future modifications in strategy are needed.

Fetal risk associated with rubella vaccine: an update.

One hundred nineteen women susceptible to rubella received RA27/3 vaccine, 94 received either Cendehill or HPV-77 vaccine, and one received a vaccine of unknown strain in the three months before or after their estimated date of conception. They gave birth to 216 living infants free of abnormalities compatible with the congenital rubella syndrome (CRS). The maximum theoretical risk for CRS for these infants was 1.7%. Four of these infants born to susceptible women had laboratory evidence of subclinical infection (three after receiving Cendehill or HPV-77 vaccines and one after receiving RA27/3 vaccine) but were normal at birth and at subsequent follow-up examinations. Rubella virus was isolated from the products of conception for only 3% (1 of 32) of cases involving susceptible women who received RA27/3 vaccine; the reported rate of virus isolation for Cendehill and HPV-77 vaccine is 20%. The available data indicate that if vaccination occurs within three months of conception, the risk is negligible. However, since the actual risk may not be zero, women known to be pregnant should not be vaccinated, and conception should be avoided for three months after vaccination.