5 Things to Know About Covid-19 and Delta Variant

1. Getting vaccinated prevents severe illness, hospitalization, and death; it also helps reduce the spread of the virus in communities.

• Unvaccinated individuals should get vaccinated and continue masking until they are fully vaccinated.
• With the Delta variant, this is more urgent than ever. The highest spread of cases and severe outcomes is happening in places with low vaccination rates.

1. Data show Delta is different than past versions of the virus: it is much more contagious.

• Some vaccinated people can get Delta in a breakthrough infection and may be contagious.
• Even so, vaccinated individuals represent a very small amount of transmission occurring around the country.
• Virtually all hospitalizations and deaths continue to be among the unvaccinated.

1. In areas with substantial and high transmission, CDC recommends that everyone (including fully vaccinated individuals) wear a mask in public indoor settings to help prevent spread of Delta and protect others.
2. CDC recommends that community leaders encourage vaccination and masking to prevent further outbreaks in areas of substantial and high transmission.
3. CDC recommends universal indoor masking for all teachers, staff, students, and visitors to K-12 schools, regardless of vaccination status. Children should return to full-time in-person learning in the fall with layered prevention strategies in place.

Learn more about guidance for fully vaccinated people.

What changed from 2 months ago when CDC said vaccinated people did not need to mask?

• Delta variant is surging: it has quickly grown from less than 1% of cases in May to more than 80% now.
• Delta spreads about twice as easily from one person to another than previous strains of the virus.
• We are constantly evaluating data and monitoring the science to determine what responses may be needed and given emerging evidence that some vaccinated people can get or spread Delta, we are recommending people in substantial and high transmission areas consider masking, even if they’re fully vaccinated.
• Importantly, the vaccines can help prevent Delta from spreading even further. Most transmission happening around the country is among unvaccinated people and in areas with low vaccination rates. We need more people to get vaccinated to stay ahead of changes in the virus.

Should vaccinated people worry they are spreading the virus?

• Vaccinated individuals represent a very small amount of transmission occurring around the country. Most vaccinated people are protected from the virus – breakthrough cases occur in only a small proportion of vaccinated people and the vast majority are avoiding serious illness, hospitalization, or death.
• If you get vaccinated, your risk of infection is ~3.5-fold lower, your risk of getting ill from COVID is over 8-fold lower, and your risk of hospitalization or death is ~25-fold lower.
• But emerging science suggests some vaccinated people can be contagious if they get Delta.
• In areas of substantial and high transmission, CDC recommends that vaccinated people should wear a mask in public indoor settings to prevent spread and protect themselves and others.

Does this mean the vaccines aren't working as expected?

• No. The 162+ million fully vaccinated Americans have a very strong degree of protection against the variants, including Delta. They are overwhelmingly avoiding severe illness, hospitalization, and death. Unvaccinated individuals account for virtually all the hospitalizations and deaths in the U.S.
• Despite seeing case numbers similar to the surge we experienced last summer, deaths are down more than 70% thanks to vaccination.
• This is further proof that getting fully vaccinated is the best thing you can do to protect yourself and those around you.

How rare is transmission by the vaccinated?

• We are continuing to monitor available data, but we know vaccinated people represent a very small proportion of transmission occurring.
• For example, example, some data out of Israel showed that as little as 13% of vaccinated people with a breakthrough infection were spreading the virus, with 80% not spreading at all.
• It's important to remember breakthrough infections occur in only a small proportion of vaccinated people and of the breakthrough infections, transmission by the vaccinated appears to only be a small part of overall spread of the virus.

If you are vaccinated but asymptomatic, can you spread the virus?

• We do not have data to inform the likelihood of asymptomatic spread among vaccinated people, but expect that it would be relatively low.
• It is possible that those who are presymptomatic – meaning infected and about to develop symptoms – may transmit the virus. Because we cannot distinguish between presymptomatic and asymptomatic infections, CDC recommends that fully vaccinated people in areas of substantial and high transmission wear a mask, particularly if they live with someone who is immunocompromised, unvaccinated, or at risk of severe disease

If vaccinated people can spread the virus, shouldn’t everyone wear a mask not just those in high transmission areas?

• If you are in a low transmission area, your overall risk of getting Delta as a vaccinated person is lower.
• You can still consider whether you want to take the extra precaution of wearing a mask (particularly if you live with someone who is immunocompromised, unvaccinated, or at risk of severe disease), but at this time we are focused on reducing transmission and therefore urge everyone to get vaccinated and, in areas with substantial or high transmission, to wear a mask in indoor public spaces.

What data is this decision based on?

• We are constantly reviewing emerging data and evidence on the Delta variant. This update is based on recent data both here in the United States and in other countries that show a small proportion of fully vaccinated people may be infected with Delta and transmit it. 

Source: Centers for Disease Control