Yesterday, Dr. Sharon Alroy-Preis, Israel’s Director of Public Health Services, was interviewed on the CBS program Face the Nation. She was very impressive as she was the only guest who spoke directly from real world data, specifically from Israel’s COVID vaccination experience.
She said several important things and reinforced some of the comments I made in my last post.
Her first comment reiterated that the RNA COVID vaccine (Israel almost exclusively used the Pfizer vaccine) was highly effective against the Delta variant. A drop in efficacy six months after immunization reduced protection against delta infection from 95%+ to over 80%.
This 10% reduction in vaccine protection six months after vaccination was seen predominantly in people over the age of 65 and did not reduce the vaccine’s efficacy in preventing hospitalization or death. This correlated well with the U.S. data showing an eight-fold reduction in infectivity with the Delta variant and 25-fold reductions in hospitalization and death.
Based on these findings, Israel is recommending COVID-19 vaccine booster shots only in the elderly, at risk individuals with other medical problems, or in people with compromised immune systems.
In addition, not only were vaccinated people less likely to be infected by the Delta variant, but in Israel’s experience, vaccinated individuals rarely transmitted the virus if they become infected. Only about 10% of COVID infected, vaccinated individuals appeared to transmit infection, and each vaccinated person infected an average of only one other individual. This is very different from the 10 individuals that each unvaccinated, infected individual is thought to infect.
This information suggests that the CDC’s presumption that infected, vaccinated individuals have an equal potential (to the unvaccinated) to infect others is incorrect. Again, the CDC presumption was based solely on swab PCR data from a single study and therefore did not have a definitive scientific basis.
The bottom line is that even with the Delta variant, the significant risk for spreading infection still comes from unvaccinated people that develope COVID-19.