Vaccinated people need to mask up again, according to the U.S. Centers for Disease Control and Prevention. On July 27, 2021, the CDC recommended that everyone in areas with high Covid-19 infection rates wear masks in public indoor spaces, regardless of vaccination status.
It’s a reversal from the CDC’s May 2021 advice that the fully vaccinated could leave their masks at home and brought U.S. guidelines more in line with World Health Organization recommendations.
The Conversation asked Peter Chin-Hong, a physician who specializes in infectious diseases at the University of California, San Francisco, to help put into context the science behind the changing messages.
What science supports masking after vaccination?
Masks help stop the spread of the coronavirus. They’re a literal layer between you and any virus in the air and can help prevent infection.
The reason public health officials are calling for more mask-wearing is that there is clear and mounting evidence that – though rare – breakthrough COVID-19 infections can occur in people who are fully vaccinated. This is particularly true with emerging variants of concern. The good news is that Covid-19 infection, if it does happen, is much less likely to lead to serious illness or death in vaccinated people.
Some conditions make a breakthrough infection more likely in a vaccinated person: more virus circulating in the community, lower vaccination rates and more highly transmissible variants.
If vaccinated people can get infected with the coronavirus, they can also spread it. Hence the CDC recommendation that vaccinated people remain masked in indoor public spaces to help stop viral transmission.
Where will the guidelines apply?
The CDC mask recommendation targets areas in the U.S. with more than 50 new infections per 100,000 residents or that had more than 8% of tests come back positive during the previous week. By the CDC’s own definitions “substantial” community transmission is 50 to 99 cases of infection per 100,000 people per week, and “high” is 100 or more.
Los Angeles County, for example, far surpassed that mark in mid-July, with more than 10,000 coronavirus cases per week.
Using these criteria, the CDC guidance applied to 63% of U.S. counties on the day it was announced.
Who’s actually protected by masking recommendations?
The recommendation that fully vaccinated people continue wearing masks is primarily intended to protect the unvaccinated – which includes kids under age 12 who are not yet eligible for vaccines in the U.S. The CDC further recommends masking in public for vaccinated people with unvaccinated household members, regardless of local community transmission rates.
Unvaccinated people are at a substantially higher risk of getting infected with and transmitting SARS-CoV-2, and of developing complications from COVID-19.
How do new variants like delta change things?
Preliminary data suggests that the rise of variants like delta may increase the chance of breakthrough infections in people who received only their first vaccine dose. For instance, one study found that a single dose of the Pfizer vaccine had an effectiveness of just 34% against the delta variant, compared with 51% against the older alpha variant in terms of warding off symptomatic disease.
The data is more reassuring for those who have been fully vaccinated. After two doses, the Pfizer vaccine still provides strong protection against the delta variant, according to real-world data from Scotland and a variety of other countries; and in preliminary studies out of Canada and England, researchers noted only a “modest” decrease in effectiveness against symptomatic disease, from 93% for the alpha variant to 88% for delta.
Other recent preliminary reports from highly vaccinated countries like Israel and Singapore are sobering, however. Before the delta variant became widespread, from January to April 2021, Israel reported that the Pfizer vaccine was 97% effective in preventing symptomatic disease. Since June 20, 2021, with the delta variant circulating more widely, the Pfizer vaccine has been only 41% effective in preventing symptomatic disease, according to preliminary data reported by Israel’s Ministry of Health in late July. An analysis using government data from Singapore demonstrated that 75% of recent COVID-19 infections were in people who were at least partially vaccinated – though most of them were not severely ill.
In all reports and studies, however, vaccines remain very good at preventing hospitalizations and severe disease due to the delta variant – arguably the outcomes we most care about.
All of this emerging data supports the WHO’s global recommendation that even fully vaccinated individuals continue to wear masks. Most of the world still has low vaccination rates and uses a range of vaccines with variable efficacies, and countries have different burdens of circulating SARS-CoV-2 virus.
With U.S. case counts and breakthrough infection numbers headed in what public health officials consider the wrong direction, it makes sense that the CDC would modify its masking recommendations to be more conservative.
What conditions in the US warrant masking up (again)?
It makes sense that the CDC didn’t immediately change its recommendations to fall in line with the WHO’s June guidelines. With an overall high countrywide vaccination rate and a low overall Covid-19 hospitalization and death burden, the U.S. has a Covid-19 landscape very different from that in most of the world.
Additionally, some experts worried that an official message that the vaccinated should don masks might dissuade unvaccinated individuals from seeking vaccines.
But as President Joe Biden put it on July 27, “new research and concerns about the delta variant” are behind the CDC’s change in masking recommendations.
Some locations are seeing further increase in community transmission, even among vaccinated people. New preliminary research yet to be peer reviewed suggests the delta variant is associated with a viral load a thousand times higher in patients than seen with older strains. And early reports show infected vaccinated people with the delta variant can carry just as high an amount of virus as the unvaccinated that they can in turn spread to others.
The shifting recommendations don’t mean that the old ones were wrong, necessarily, only that conditions have changed. The bottom line? Masks do help cut down on coronavirus transmission, but it’s still vaccines that offer the best protection.
Peter Chin-Hong is Associate Dean for Regional Campuses, University of California, San Francisco.
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David Schaefer says
If the majority of people would have listened in the first place we would not be in this position. These anti- vaccine people have no one to blame but themselves.
Irwin M. Fletcher says
It would seem that as long as we are all not working in one direction for control or eradication, we will continue to let this pandemic control us. We need to face the fact that COVID 19 is a moving target and collectively work for a resolution. Is it that difficult to follow some basic guidelines to keep us healthy? Folks we are all in this together, COVID doesn’t care what you look like, how you vote or what your ideals are. Let’s stop with the nonsense and focus on our future, we all have one common enemy right now. Stop with the unproductive rhetoric and focus on end game.
Trailer Bob says
Well if that commentary was to get people paranoid or confused…it worked.
Seems some of my best days are days that I didn’t read too much news.
The story changes almost daily with the COVID crap.
What’s next…”COVID has been found on the moon”?
I guess I was over confident after I got the vaccine…who knew???
Not a unicorn says
Trailer Bob, the reason things change with Covid is bc it is a virus that changes. Scientists must keep up with it by studying what it does. Science is not static or stuck. Science has to change as the virus evolves and changes itself due to people who perpetrate it by not getting the vaccine and masking to slow and eventually stop the mutations and spread.
A virus is not a politician and it will do what it will. We all need to keep abreast of the latest findings by scientists so that we are accurately informed.
Seems the only entities that remain static are the conspiracies and the people that believe them, to divide us and worsen the pandemic.
joe says
“The story changes almost daily with the COVID crap.”
Actually, there is no “story” that “changes almost daily” – it’s simply public health officials trying their best to adapt to the change in the spread of a variant that is much more transmissible and has much higher viral loads (even in vaccinated people, apparently – and I am one of those fully vaccinated.) – what has changed is the virus AND the behavior of far too many people who heard the earlier CDC guidance that fully vaccinated people could unmask to mean that everyone could just say the hell with it, drop their mask and behave like the virus was beaten.
It’s the irresponsible behavior of far too many of those who refuse to be vaccinated that’s responsible for the current conditions, not the doctors and scientists.
Steve says
Its Reality not a contrived Global Story. Covids found in FPC should be your concern not the Moon. The Facts/Stats are in.From One whom talks of All the negativity may want to keep it Real. Virus =Mutation/Change/Dynamic= Spread in Unvaxxed. Containment is possible except for the paranoid or confused
Concerned Citizen says
I wear a mask per CDC guidelines. Whether you do or not that’s your busniess.
And should go the same for you. If you aren’t a Government Official or Law Enforcement Officer with special Mask Enforcement Authority then leave people alone. It was bad enough the first time around with self appointed/self important Mask Karens.
I won’t be polite this time when getting out of my vehicle in an open parking lot and being confronted about putting a mask on.
Mark says
You should wear your mask in public tho, that would most Def include a parking lot in public. Let’s be safe and work together to win this war against covid. We are losing right now but if we work together , stay home , collect unemployment and social distance
Shelly says
Even if everyone was vaccinated we’d still be in this position in which we have Biden to thank for. After all, he let millions of illegals across the border, no masks, no COVID testing for them and no vaccines. Thousands of illegals who crossed the border had COVID and they were being bussed to whatever State they requested to go to. What’s up with that? Why isn’t anyone bringing that up? US Americans have to get the jab but illegals don’t? Why do they have more rights and freedom than us? What happened to Fauci and Biden saying that once you get the vaccine, you’re fully protected against the virus? I was better off not getting this useless experimental drug.
joe says
“What happened to Fauci and Biden saying that once you get the vaccine, you’re fully protected against the virus?”
Actually, they never said that – nor did any doctor – no vaccine is perfect – these vaccines were never promised to provide 100% protection – the estimates were in the high 90’s –
Please, get your facts right
Tired says
It mutated due to people not getting vaccinated or masking. It’s a worse variant now. There will be more variants. A virus wants to keep itself alive so it changes to better infect you.
Why do you and some others wish to allow this to continue? It’s like you love the drama of people getting sick and dying. Your actions have repercussions why do you and some others continue to speak like children who lack the cognitive abilities to comprehend what is happening? So you make up some wild conspiracy that the whole world is out to get you. Due to this denial of facts, this is going to get way worse. Mark my words, the virus is going to get so much worse. This based on science will happen. Protect yourself.
The dude says
Jesus…
Turn off the Fox News. That shit will rot your brain.
jake says
Another one “speaking from knowledge”. Dude, not sure who you are referring too, everyone on Fox News has been vaccinated, and everyday they are asking people to get vaccinated. What they do point out is the hypocritical bullshit for those that “do as I say, and not as I do”. Yes they say you have a choice, however they will also state the fact that if you are not vaccinated, your chances of getting sick are far worse. The only “shit will rot your brain” is what I see from those still ignorant, like you, making statements about things you know nothing about.
David Schaefer says
Lady get a grip. If you get sick I bet you will be another one crying WHY DIDNT I GET THE SHOT. Its apperent that you don’t follow the news much or your to busy on the Trump group page.
Steve says
WHATABOUTISM alive and well in FPC SMH
Grandma says
We chose to get the vaccine to protect ourselves and get rid of the mask. Now we have to wear it to protect those who chose to not get the shot. That is their right but we shouldn’t be suffering for their choice.
mark101 says
Not really even if you are vaccinated you can still get infected. The current evidence shows that vaccines provide some protection from infection and transmission, but that protection is less than that for serious illness and death. But yep the I don’t care crowd are the ones NOW ending up in the ICU fighting for their lives because of pure stubbornness. And some parents watch their children ending up in the ICU. Case in point, 15 year old south Fla girl. https://www.nbcmiami.com/news/local/why-my-daughter-broward-teen-hospitalized-in-icu-with-covid-19/2506704/
Harold Benson says
I have a serious comment: The US government, media, CDC etc. have been touting vaccines so long and so hard, but we cannot expect vaccines to get us out of peril
MAIN REASON: Vaccines cannot be developed quickly enough to protect us against variants, and new variants of danger will arise again and again as long as large nos. of people in the world are not vaccinated.
SOLUTION IS SIMPLE: MASK UP INDOORS ALWAYS. MAKS HELP PROTECT AGAINST ALL VARIANTS: VACCINES DO NOT!!! IT”S THAT SIMPLE>