Most events occurring at a higher rate after LAIV were found in comparison with unvaccinated controls, while most events occurring at a lower rate after LAIV were found in comparison with TIV-vaccinated controls. These differences are most likely the result of underlying differences in the nonrandomized comparison groups this website that
remained despite subject matching. Despite efforts to exclude individuals with high-risk underlying medical conditions from the analysis populations, it is likely that TIV-vaccinated controls had a poorer health status relative to LAIV-vaccinated subjects because LAIV, unlike TIV, is not recommended for adults with asthma, immunosupression, and other underlying medical conditions . This selection bias could explain the decreased rates of respiratory events, SAEs, hospitalizations, pregnancy-related events, diabetes, AIDS, and SLE among LAIV recipients. In addition, an underlying bias may exist between the LAIV recipients and unvaccinated controls since individuals who do not seek vaccination may be less likely to seek other routine medical care. Furthermore, Kaiser health system members are prompted to receive recommended preventative health services or schedule consultations with specialists at the time of vaccination. Therefore, fewer MAEs related to routine preventive care (well visits, vision disorder, obesity and benign lesions) would be expected to be reported for unvaccinated Y-27632 cost controls in comparison
to those vaccinated with LAIV. A few medical events occurred at a higher rate after LAIV in comparison to more than one control group. Mastitis, breast lump/cyst and sleep disorders occurred at a higher rate after LAIV compared with TIV or unvaccinated controls. There is no clear biological relationship between LAIV vaccination and these events. Also, after correcting for multiple comparisons, these events were not statistically increased and as a result may be due to chance alone given the large number of comparisons
made in this analysis. Ketanserin Although LAIV is not approved for use in pregnant women, inadvertent vaccination does rarely occur. Currently, there is little information available on fetal outcomes . Of the 54 live births with information available reported in this study, there were 3 premature births (5.6%), and 1 child born with clinodactyly (1.9%), a shortening and curvature of the fifth finger. However, a causal association between LAIV and clinodactyly is unlikely in this instance as LAIV was administered to the mother late in the second trimester, after the period of fetal limb development. Overall, rates of fetal outcomes in this study were consistent with rates observed in the offspring of the general population  and . Other studies reporting safety events associated with LAIV in pregnant women support our results. VAERS data indicated that 27 pregnant women from 2003 to 2009 received LAIV, and no congenital anomalies or adverse fetal events were reported .