While most COVID vaccines are thought to largely protect against all known variants, none is 100 percent effective. The WHO also advises vaccinated people to keep taking precautions such as staying in well-ventilated areas and avoiding crowds. When asked about the WHO’s advice for vaccinated people by the New York Times, a CDC spokesperson referred to its existing guidance and gave no indication those recommendations would be altered. “Breakthrough” infections in fully vaccinated people can occur, though they are rare and usually less severe. The CDC’s guidance for unvaccinated people continues to be that they should wear a mask in public indoor settings and follow other public health precautions, such as distancing and keeping to well-ventilated spaces.