In a split from current CDC guidance, the World Health Organization (WHO) on Friday said that people fully vaccinated against Covid-19 should continue to wear masks and maintain social distance due to the highly transmissible delta coronavirus variant spreading rapidly worldwide.

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WHO says fully vaccinated people should still wear masks

According to the New York Times, WHO officials urged people vaccinated against Covid-19 to wear masks and take other safety precautions, given that a large portion of the world remains unvaccinated while highly contagious variants spread.

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The emergence of new variants "makes it even more urgent that we use all the tools at our disposal to prevent transmission," including both vaccines and public health safety measures, Tedros Adhanom Ghebreyesus, director-general of WHO, said in a news conference on Friday.

WHO officials cited dangers posed by the delta variant, which the organization said was currently present in at least 92 countries and is the fastest and fittest variant of the virus yet. According to the Times, research indicates that certain vaccines are slightly less effective against the delta variant—and considerably less effective if people have received just one dose of a two-dose vaccine regimen.

In fact, several countries with comparatively high rates of vaccination have seen an increase in infections driven by the delta variant, the Times reports. For instance, Britain, where about half of the population has been fully vaccinated and about two-thirds has been at least partially vaccinated, is grappling with a surge in delta-related Covid-19 infections. And in Israel, which reports one of the highest rates of vaccination in the world, an increase in Covid-19 cases attributed to the delta variant has spurred the government to reinstitute some mask requirements. 

According to WHO officials, if people are not careful, the delta variant "will 'pick off' the most vulnerable people, especially in places with low Covid vaccination rates. " The delta variant has the potential "to be more lethal because it's more efficient in the way it transmits between humans and it will eventually find those vulnerable individuals who will become severely ill, have to be hospitalized, and potentially die," Mike Ryan, executive director of WHO's health emergencies program, said.

Bruce Aylward, a senior adviser to WHO, added, "What we're saying is, 'Once you've been fully vaccinated, continue to play it safe, because you could end up as part of a transmission chain.' You may not actually be fully protected."

"People cannot feel safe just because they had the two doses. They still need to protect themselves," Mariangela Simao, WHO assistant director-general for access to medicine and health products, said.

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"Vaccine alone won't stop community transmission," she continued. "People need to continue to use masks consistently, be in ventilated spaces, hand hygiene ... the physical distance, avoid crowding. This still continues to be extremely important, even if you're vaccinated, when you have a community transmission ongoing."

Reaction

Currently, CDC guidance says that fully vaccinated Americans do not need to wear masks indoors or maintain a distance of six feet from others. When asked about the latest WHO recommendations, a spokesperson for CDC gave the New York Times no indication that guidance would change.

Some experts agreed with WHO's recommendations. Given how quickly the variants are spreading, "the vaccine approach is not enough," Eric Feigl-Ding, a senior fellow at the Federation of American Scientists, said. "We're not at the level of vaccinations where we can release the brakes on everything else and herd immunity will grind transmissions to a halt."

However, other experts disagreed, the Times reports, saying new guidance should be tailored to specific communities based on local vaccination and transmission rates.

"The WHO is looking at a world that is largely unvaccinated, so this makes sense," Ashish Jha, dean of the Brown University School of Public Health, said.

Jha added that, in some areas of the United States, it may still be appropriate to wear masks, and guidance should be tailored to those areas. "If I were living in Missouri or Wyoming or Mississippi, places with low vaccination rates, I would not be excited about going indoors without wearing a mask—even though I'm vaccinated." (Lovelace, CNBC, 6/25; Rabin, New York Times, 6/29)