DETROIT – Many people want to know why the CDC suddenly decided to lift mask recommendations for people who are fully vaccinated.
Some of the updates in mask guidance for fully vaccinated people come from a study that was published last Friday in the CDC’s publication, the Morbidity and Mortality Weekly Report. That study, and others that have supported the effectiveness of the mRNA vaccines in particular, are what prompted the CDC to change the guidelines for mask use.
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While the change was announced suddenly, it came after gradually increasing data over months that indicated we should have high confidence in the ability of the vaccines to protect people from severe disease and death.
The most recently published study in the MMWR confirmed that in real world use over the period from January to March of this year the two mRNA vaccines from Pfizer and Moderna were 94 percent effective at preventing symptomatic COVID-19 after both doses.
A separate Israeli study looking at the efficacy of the Pfizer vaccine, published early May in Jama, found similar results. Vaccinated people had a high level of protection against both symptomatic and asymptomatic infection.
None of the published studies looking at the real world effectiveness of the vaccines have been able to address the Johnson and Johnson vaccine because it hasn’t been out as long. However, there is preliminary data on a similar vaccine, Astrazeneca, showing that it too is effective.
Taken together, all of the most current data looking at the effectiveness of the vaccines is very supportive of the updated recommendation. That fully vaccinated people, in ordinary settings, are safe to carry on without masks if they choose. Being very practical, no one believed masks and distancing were going to stay forever. The data on vaccines is what has tipped the scale.
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