A Roundup of CDC Studies: Vaccine Effectiveness, Vaccines in Teens, and Delta in Schools
A summary of the latest Covid-19 research
It’s impossible to keep up with every new study that comes out about Covid-19, but every so often I’ll summarize a few of the recent ones to keep people up to date on the more significant research. Today’s roundup includes the findings from three different Morbidity and Mortality Weekly Reports from the CDC.
Pfizer and Moderna vaccine effectiveness drops to 66% against delta
Vaccine effectiveness fell about 25 points once delta arrived on the scene, according to a CDC study of health care workers. Although the mRNA vaccines were about 91% effective before delta, their effectiveness dropped to an average 66% effective during the weeks when the delta variant dominated.
The researchers used data from an ongoing surveillance program called HEROES-RECOVER Cohorts, in which health care workers, first responders, and other essential workers from six states undergo weekly PCR Covid-19 testing.
Most (83%) of the 4,217 participants were fully vaccinated. About two-thirds (65%) of those fully vaccinated had received the Pfizer vaccine, a third (33%) had received Moderna, and 2% had received…
