New study says vaccines can't stop the delta variant alone


Researchers recommended the use of masks and physical distancing until almost everyone is vaccinated.

By Joseph Guzman | July 30, 2021

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“We found that a fast rate of vaccination decreases the probability of emergence of a resistant strain,” researchers wrote.

“Counterintuitively, when a relaxation of non-pharmaceutical interventions happened at a time when most individuals of the population have already been vaccinated, the probability of emergence of a resistant strain was greatly increased,” the study says.

The study backs up an internal report from the Centers for Disease Control and Prevention that says the delta variant is far more transmissible than older strains and may cause more severe disease.


A new study is emphasizing the importance of both vaccinations and mitigation measures, such as masks and physical distancing, to curb the spread of the coronavirus and stop the threat of new variants.

The research published in Nature Scientific Reports warns that vaccines alone will not stop the emergence of new coronavirus strains, and the innoculations could actually accelerate the evolution of new variants that evade their protection if safety measures like masking are stopped prematurely.

According to the study, the virus will not stop changing until almost everyone has been fully vaccinated.

“We found that a fast rate of vaccination decreases the probability of emergence of a resistant strain,” researchers from the Institute of Science and Technology Austria wrote in the study.

“Counterintuitively, when a relaxation of non-pharmaceutical interventions happened at a time when most individuals of the population have already been vaccinated the probability of emergence of a resistant strain was greatly increased,” researchers wrote.

“Our results suggest that policymakers and individuals should consider maintaining non-pharmaceutical interventions and transmission-reducing behaviors throughout the entire vaccination period,” the study says.

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The study backs up an internal report from the Centers for Disease Control and Prevention (CDC) that says the delta coronavirus variant is far more transmissible than older strains and may cause more severe disease.

The report said there’s evidence fully vaccinated people could pass on the delta variant just as easily as those who have yet to be vaccinated, although vaccines are still effective at protecting people from becoming seriously ill and reduce the chance of hospitalization or death.

The CDC estimates about 35,000 vaccinated people in the U.S. may be getting infected with the virus each week, although most new infections are occurring among the unvaccinated.

The health agency early this week changed its mask guidance, advising fully vaccinated Americans to wear masks inside when in areas with “substantial” and “high” transmission of COVID-19.