In New York, health officials told the Centers for Disease Control and Prevention on Sept. 7 that that they were seeing a strain of E. coli that might match strains being reported in other states, according to Claudia Hutton, a spokeswoman for the state's Department of Health.
Vaccine efficacy against matching strains was consistently high (73% 82%) throughout the study, including the entire period of the influenza season during which influenza activity was above the epidemic threshold.
In a randomized, double-blind comparison of live, attenuated vaccine with inactivated vaccine in children, the authors reported a relative efficacy against culture-confirmed influenza illness caused by poorly matched strains that was higher than that estimated for well-matched strains (VE SP = 58%, 95% CI: 47, 67) (11).
The theoretical efficacy of the pandemic vaccine (with vaccine strains matching pandemic strains), was considered to be much higher (between 0.3 and 0.7) in agreement with literature values (see Table S1).
There is significant interest in estimating vaccine efficacy for poorly matched strains because the prepandemic vaccines currently being developed will likely be poorly matched to the pandemic strain when a pandemic strain emerges.
Still, matching the strains is not definitive proof that the same person sent the material.
While in all infants colonized by E. faecalis, some polymorphic locations could be identified, in most infants, polymorphisms matching strains of other infants were undetectable (infants #2, #6, #8, #9).
However in this study no neonatal isolates were recovered which matched strain 716.
Population studies remain to be done on these isolates to determine if the observation of a re-established dominance of prn1 containing vaccine matching strains in Queensland may be a geographic specificity related to a clonal expansion of a distinct B. pertussis population.
