Kari Bohlke

Influenza vaccination in children with asthma in Health Maintenance Organizations

We assessed vaccination coverage and predictors of influenza vaccination in asthmatic children in four large Health Maintenance Organizations. We studied 68,839 children with asthma at four Health Maintenance Organizations (HMOs) in the 1995-1996 influenza season and 34,032 children at two HMOs in the 1996-1997 influenza season. In both seasons only 9-10% were vaccinated against influenza. Children who were hospitalized, had an emergency department visit for asthma or a prescription for a beta-agonist prior to the influenza season, were more likely to be vaccinated. Overall, 61% of the unvaccinated asthmatic children had made an outpatient clinic visit during months when influenza vaccination would have been appropriate. Vaccination coverage could be increased by taking advantage of all opportunities to vaccinate children with asthma whenever they make clinic visits in the fall and early winter.

Postpartum varicella vaccination: is the vaccine virus excreted in breast milk?

OBJECTIVE To evaluate whether the varicella vaccine virus is detected in breast milk after vaccination of breast-feeding women and whether there is serologic evidence of exposure of the infant to varicella virus after maternal vaccination. METHODS We enrolled women identified as varicella seronegative during routine prenatal screening at Group Health Cooperative. Participants received the first dose of varicella vaccine at least 6 weeks postpartum and the second dose at least 4 weeks later. They collected ten breast milk samples after each vaccine dose. Breast milk samples were tested for varicella-zoster virus by polymerase chain reaction (PCR). Serum specimens were collected from the mothers 1 month after each vaccine dose, and peripheral blood from their infants was collected onto filter spots 1 month after the mothers second dose. These samples were tested for varicella immunoglobulin (Ig) G by whole-virus enzyme-linked immunosorbent assay (ELISA), or by the more sensitive glycoprotein ELISA. When possible, filter spots from the infants were also tested by PCR for the presence of varicella zoster virus deoxyribonucleic acid (DNA). RESULTS Twelve women were enrolled; all seroconverted after the first vaccine dose. Varicella DNA was not detected by PCR in any of the 217 postvaccination breast milk specimens. None of the infants was seropositive. Samples from six infants were tested for varicella zoster virus DNA by PCR, and all were negative. CONCLUSION We found no evidence of varicella vaccine virus excretion in breast milk. These findings suggest that postpartum vaccination of varicella-susceptible women need not be delayed because of breast-feeding.

Measles vaccination and inflammatory bowel disease: controversy laid to rest?

AbstractThe increasing incidence of Crohn’s disease has lead to speculation about changes in exposures to environmental or infectious agents. Considerable attention has focused on the role of measles infection and/or vaccination in the pathogenesis of Crohn’s disease and ulcerative colitis.Current evidence regarding the association between measles vaccination and inflammatory bowel disease (IBD) comprises analytic epidemiological studies, a case-series report and ecological studies. The first of these, a 1995 cohort study, found an association between measles vaccination and Crohn’s disease and ulcerative colitis, but was widely questioned on methodological grounds. This was followed by a 1997 case-control study showing no association between measles vaccination and IBD. In 1998, public concern was rekindled by a report of 12 children with nonspecific colitis, ileal-lymphoid-nodular hyperplasia, and developmental disorders largely attributed to measles-mumps-rubella vaccine, but the nature of the report limited its scientific conclusions. Two additional studies, one case-control and one cohort, then followed and neither found an association with measles vaccination. Of the several ecological studies of measles vaccine coverage or measles schedule changes, none found an association with rates of IBD.The role of measles infection in IBD has been examined more extensively with studies of in utero measles exposure, measles infection early in life, and laboratory based investigations. An initial report of high rates of Crohn’s disease among pregnancies affected by measles infection was followed by negative studies. Numerous case-control and ecological studies of children with measles infections early in life have also had discordant findings. Of three recent cohort studies, two showed no relationship between infection with early measles exposure and risk for IBD, while one found an approximate 3-fold elevation in risk. Laboratory investigations into persistent measles infection and IBD have been contentious. While some investigators have claimed to find persistent measles infection among patients with IBD, others, using highly sensitive polymerase chain reaction techniques, have not been able to replicate the findings. Recent controversy has centred on whether there is any evidence for molecular mimicry in the pathogenesis of IBD. In summary, available evidence does not support an association between measles-containing vaccines and risk of IBD, nor between measles infection and IBD. While further research is necessary into the causal factors underlying Crohn’s disease and ulcerative colitis, continued public education efforts are needed to reassure the public about vaccine safety and to prevent declines in vaccine coverage.