Last week, I took to social media to ask people what their biggest questions were about life after the Covid-19 vaccine. Within minutes, my post had dozens of comments. “When can I hug my dad? That’s all I want to do,” one person wrote. “Indoor dining at a restaurant? Airplane travel?” another asked. I also got questions about whether it’s safe to congregate indoors with other vaccinated people, whether vaccinated people can spread Covid-19 without knowing it, and what it means if some family members are vaccinated and others aren’t.
These are all excellent questions. Unfortunately, there aren’t clear, black-and-white answers to many of them. We still don’t have the data we need to answer some questions definitively while others will depend on a person’s situation and risk tolerance. Nevertheless, I called five people — two infectious disease physicians, an immunologist, and two public health scientists — to get their thoughts. They emphasized that we shouldn’t think of vaccination as a carte blanche; instead, we should think of it as an additional (and very helpful) layer of protection. The more layers we have, the safer we will be.
Can vaccinated people still spread Covid-19?
This question is important because it shapes the answers to all of the others. The two vaccines that are approved for use in the U.S., made by Moderna and Pfizer, and the vaccine made by Johnson & Johnson that is being considered for Food and Drug Administration approval now, were all evaluated in clinical trials to see if they could do one thing and one thing only: keep vaccinated people healthy. Thankfully, the three vaccines do this very well. People who received the Moderna or Pfizer vaccines in the clinical trials were 94% and 95% less likely, respectively, than unvaccinated people to develop symptoms of Covid-19. People who got the Johnson & Johnson vaccine were 66% less likely than unvaccinated people to develop moderate to severe Covid-19 symptoms, but importantly, they were fully protected against hospitalization and death.
Scientists Are Optimistic That the Vaccine Will Partially Prevent Infection
The data are still out, but scientists say those who are immunized will shed less virus than those who aren’t
What these trials were not designed to do, however, was determine whether the vaccines prevent people from spreading Covid-19. (Many researchers wish the pharmaceutical companies had incorporated this question into their clinical trials; they certainly could have.) You may be wondering: How is it even possible for a vaccinated person, who feels totally fine, to spread Covid-19? It’s counterintuitive, I know. But some vaccines are able to prevent symptoms without preventing infection. For instance, the inactivated polio vaccine (IPV), which is routinely given to children in the U.S. to prevent polio, does not prevent the polio virus from replicating in vaccinated people and being shed in their bowel movements; it just prevents vaccinated people from getting sick.
Still, most scientists believe the Covid-19 vaccines will reduce spread. “It would be very surprising if they didn’t,” says Jennifer Dowd, PhD, an associate professor of demography and population health at the University of Oxford in the U.K. The question is, how much will they reduce spread? At this point, we don’t know for sure. Thankfully, “transmission studies are being planned, and that will give a clearer-cut answer,” says Angela Shen, ScD, MPH, a visiting research scientist at the Vaccine Education Center at the Children’s Hospital of Philadelphia. Experts aren’t sure when we’ll have results, but it could be as soon as a few weeks or months.
That said, there have already been promising hints. In the Moderna vaccine trial, researchers administered nasal swabs to subjects when they came in for their second vaccine. They found that only 15 people out of 15,210 who had received the first dose of vaccine had SARS-CoV-2 virus in their noses even though they didn’t have symptoms compared with 39 people in the group of 15,210 who didn’t receive the vaccine. In other words, the vaccine appears to have reduced the risk for asymptomatic infection by 62%. It’s “a really good sign,” Dowd says.
Earlier this month, too, in a study that has not yet been peer-reviewed, Israeli researchers calculated, based on PCR results, the amount of virus produced by people who had received the first dose of Pfizer vaccine within 12 to 28 days but who had nevertheless tested positive for Covid-19. They found that the vaccinated individuals had four-fold fewer viral particles in their noses compared with unvaccinated individuals who had Covid-19. This, again, suggests that people who have been vaccinated but who still get infected are less contagious than unvaccinated people who have Covid-19.
Also, in the Lancet on February 18, researchers reported that 15 to 28 days after receiving the first dose of the Pfizer vaccine, healthcare workers in Israel, who were regularly being tested for Covid-19, were 75 percent less likely than unvaccinated healthcare workers to test positive. And in a pre-print published on February 22, researchers in the UK reported that a week after receiving the second dose of the Pfizer vaccine, healthcare workers were 85 percent less likely to test positive for Covid-19. Both of these findings suggest that asymptomatic infections are possible, but rare, among people vaccinated with the Pfizer vaccine. (Cautionary note: Some articles have been touting an 89.4% reduced risk for asymptomatic infection based on new data from Israel, but some researchers argue that this claim is inaccurate and likely an overestimate.)
So far, then, the science suggests that although vaccinated people might be able to get and spread Covid-19, the chances of this happening are much lower than they are among unvaccinated people. Still, this remaining slice of risk is one reason why people who are vaccinated should still wear masks and maintain social distancing in public.
If I’ve been vaccinated, am I protected against the new Covid-19 variants?
This is another key question that we don’t have a clear answer to yet. Right now, researchers are most concerned about three variants that are spreading in the U.S.: The B.1.1.7 variant from the United Kingdom, the P.1 variant from Brazil, and the B.1.351 variant from South Africa. The mutations in these variants cause the virus to spread more easily between people, and early data suggest that the U.K. variant may also be more deadly.
Preliminary research suggests that the vaccines approved for use in the U.S. protect against these variants to varying degrees. In one study that has not yet been peer-reviewed, researchers at Moderna and the National Institutes of Health exposed blood from people who had received the Moderna vaccine to virus-like molecules that had been engineered to contain some of the key mutations found in the variants. Their analysis suggests that the vaccine protects just as well against the U.K. variant as against the original version of SARS-CoV-2. It works less well against viruses containing the mutations found in the South African variant, but Moderna said it believes the vaccine should still protect people against it. That’s in part because the vaccine incites more than enough protection against the original virus, so a small drop in protection may not cause problems. The vaccine wasn’t tested against all the key mutations in the Brazilian variant, but that variant contains some of the same mutations as the South African variant, so it’s possible results would be similar.
Pfizer has also found, in a not-yet-peer-reviewed study, that its vaccine works well against the U.K. strain. And earlier this month, in a study now published in Nature Medicine, researchers tested how blood taken from Pfizer-vaccinated individuals reacted to viruses that had been engineered to contain the key U.K. and South African mutations and some of the Brazilian ones. They found that the vaccinated blood was highly protective against viruses containing the U.K. mutations but slightly less protective against the South African and Brazilian mutations — but that those differences were, again, small enough to suggest that the vaccines might still protect against them.
We need to see how the vaccines “perform in real life rather than in a test tube.”
The Johnson & Johnson vaccine may not be quite as effective against the variants. According to a February analysis of the clinical trial data, the vaccine is 95% effective against the original coronavirus strain, 86% effective against the U.K. strain, and 60% effective against the South African strain. (They did not provide estimates for the Brazilian variant.) No one who received the vaccine died or had to go to the hospital, though, even when infected with one of the variants.
What does all this mean? To some degree, “we just have to sort of watch and wait and hope,” said Gigi Kwik Gronvall, PhD, an immunologist and senior scholar at the Johns Hopkins Center for Health Security. Judging from the lab data, the Pfizer and Moderna vaccines may still protect against these new variants. But ultimately, we need to see how the vaccines “perform in real life rather than in a test tube,” says Hana Akselrod, MD, an infectious diseases physician at the George Washington University School of Medicine and Health Sciences. Still, she says, “overall, the results are encouraging.”
If the grandparents have been vaccinated, can we visit them, even if we aren’t vaccinated?
In a word, yes. “If your main concern was protecting the grandparents, and they’re fully vaccinated, I think that getting together as a family is something you could consider,” Dowd says. Even if you or your kids have Covid-19 and infect them during the visit, Dowd notes, Grandma and Grandpa would probably not get seriously ill.
Of course, vaccine protection is not 100%, so there will be exceptions. And “the older people are, the more trouble their immune system has forming memories and then mobilizing defenses,” Akselrod says, so 95-year-old vaccinated grandparents are probably not going to be as well protected as 75-year-old vaccinated grandparents.
“If your main concern was protecting the grandparents, and they’re fully vaccinated, I think that getting together as a family is something you could consider.”
Still, serious Covid-19 illness after vaccination should be rare — and it’s important to remember that not seeing family poses risks, too. “Infection from Covid is not the only risk to our health. I’m very worried about social isolation and loneliness,” says Preeti N. Malani, MD, the chief health officer in the division of infectious diseases at the University of Michigan. (Regarding hugs: They’re safer than kisses, Akselrod says.)
You should not forget about the potential risks to you if you visit your vaccinated parents, though. It’s possible, especially if Grandma and Grandpa are now celebrating being vaccinated by eating out at restaurants and seeing their friends, that they could have Covid-19 when you visit and not know it — and potentially infect you (although the risk is likely small). “I’d probably be most worried right now about the 50-to 65-year-olds who are not yet vaccinated but still in danger of some serious complications if they have Covid,” Dowd says.
If that’s you — or if you are at high-risk for another reason — do what you can to mitigate risks during your visit: Spend as much time outdoors as possible, especially while eating, and have the air-conditioning fans running continuously indoors to maximize ventilation, Gronvall suggests. Even if you’re not high-risk, it’s not a bad idea to take some of these simple precautions. Encourage everyone to lay low and minimize their exposure risk in the two weeks before the visit, too. You can even consider testing everyone beforehand for added peace of mind. Masks are a judgment call, and the experts I talked to didn’t provide a blanket recommendation; but if someone in the group is unvaccinated and high-risk, you could consider wearing them.
If the grandparents live in a nursing home or assisted living facility, you’ll want to be extra careful as well. In settings like this, “even though people are vaccinated, some of them may be too frail to mount much of a response to the vaccine. You still want all the extra precautions you would have taken before they were vaccinated,” Akselrod says. In other words, wear masks and try to stay socially distanced and outside when possible.
If I’m vaccinated, can I spend time indoors without masks with other vaccinated friends?
The answer to this question depends on your situation. If you live alone or with a partner who is also vaccinated and you otherwise don’t see many other people, then getting together with vaccinated friends is probably quite safe. “I can’t really argue against that,” Dowd says. “Even if somehow you were passing [Covid-19] to each other, probably no one would even come down with anything detectable.”
The answer may not be yes, though, if you’re vaccinated but have family members at home who aren’t or if you have a job that puts you in regular contact with people who are susceptible to Covid-19. It’s possible (though probably unlikely) that your vaccinated friends could infect you, and then you could infect your partner, your kids (though kids under ten are unlikely to get very sick unless they have certain underlying conditions), or others. If we get additional data suggesting that spread among vaccinated people is unlikely, this will become less of a concern.
If I’m vaccinated and learn I’ve been exposed to Covid-19, do I have to quarantine?
If you received your final vaccine dose more than two weeks ago but less than three months ago and you do not have any Covid-19 symptoms, then no — the Centers for Disease Control and Prevention says that you do not have to quarantine if you have been exposed to Covid-19. If you develop symptoms, you should be evaluated and tested for Covid-19. And if you’ve been vaccinated but not within the two-week to three-month window, then you should still quarantine per CDC guidelines.
If I’m vaccinated, can I travel?
Yes, but again, consider your situation — and try to minimize your overall travel risks. Airplane travel itself is fairly safe, but “the tricky part about flying is really the accouterments,” Shen says. Minimize who you come into contact with on the way to and from the airport, while at the airport, and while eating.
If you’re debating driving versus flying, Malani says to remember that long-distance driving poses risks, too. Car accidents are more common when people are tired and stressed as is the case for many of us right now. Some research has found that although fewer cars have been on the road, crash rates, and especially fatal crash rates, have gone up during the pandemic. “My recommendation has been for people to fly when they need to” travel long distances, she says. A 2020 paper published in the Journal of the American Medical Association concluded that the risk of catching Covid-19 on an airplane “is lower than from an office building, classroom, supermarket, or commuter train.” And if you’re vaccinated, that risk is reduced even more.
Also, consider your circumstances. If you’re traveling by yourself or only with other vaccinated people, that’s going to be a lot safer than if you’re traveling with unvaccinated family members. Rates of Covid-19 right now are still quite high, so traveling also might also feel safer in a few months, when case counts are lower and more people have been vaccinated.
If I’m vaccinated, can I eat indoors at a restaurant? Go back to the gym?
Maybe. “For people who are vaccinated, eating out indoors is a lot safer,” Dowd says, but “it’s still one of the riskiest things we can do, especially while cases are so high.” Even if you’re vaccinated, it’s possible you could catch Covid-19 while eating out and spread it to family members or other people you come in contact with. “I keep coming back to ‘What’s going on in your life outside of that dinner?’” Akselrod says.
On the other hand, if you only live with other vaccinated people and you don’t interact with others much or at all, then eating out is probably safe — although Dowd says she would personally avoid eating indoors at restaurants until Covid-19 rates have dropped a bit more.
This advice applies to other potentially high-risk activities, too, like going back to the gym. “I kind of want to get back to the gym. And a massage would be great, too,” Dowd says. “But if I was the only one vaccinated, I don’t know — I would still definitely be worried about spreading to my husband. So I think you kind of have to look at the situation around you.”
The bottom line is that if you’re vaccinated, you’re protected from serious illness but not necessarily from infection. Although the risk that you could spread Covid-19 is almost certainly reduced, it’s possible you could still infect others. So until we have more data suggesting otherwise, it’s wise to be a bit cautious. This doesn’t mean you can’t see your extended family or do some of the things you’ve been longing to do, but don’t treat vaccination as a panacea. Keep in mind who in your life is still susceptible, and take additional precautions to keep them — and the rest of your community — safe.