Can the Covid Vaccine Protect Me Against Virus Variants?

April 15, 2021
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This post was originally published on this site

Vaccines do a good job of protecting us from coronavirus, but fear and confusion about the rise of variants have muddled the message. Here are answers to common questions.

The news about coronavirus variants can sound like a horror movie, with references to a “double-mutant” virus, “vaccine-evading” variants and even an “Eek” mutation. One headline warned ominously: “The devil is already here.”

While it’s true that the virus variants are a significant public health concern, the unrelenting focus on each new variant has created undue alarm and a false impression that vaccines don’t protect us against the various variants that continue to emerge.

“I use the term ‘scariants,’” said Dr. Eric Topol, professor of molecular medicine at Scripps Research in La Jolla, Calif., referring to much of the media coverage of the variants. “Even my wife was saying, ‘What about this double mutant?’ It drives me nuts. People are scared unnecessarily. If you’re fully vaccinated, two weeks post dose, you shouldn’t have to worry about variants at all.”

Viruses are constantly changing, and new variants have been emerging and circulating around the world throughout the pandemic. Some mutations don’t matter, but others can make things much worse by creating a variant that spreads faster or makes people sicker. While the rise of more infectious variants has caused cases of Covid-19 to surge around the world, the risk is primarily to the unvaccinated, for whom there is great concern. While vaccination efforts are well underway in the United States and many other developed countries, huge swaths of the world’s population remain vulnerable, with some countries yet to report having administered a single dose.

But for the vaccinated, the outlook is much more hopeful. While it’s true that the vaccines have different success rates against different variants, the perception that they don’t work against variants at all is incorrect. In fact, the available vaccines have worked remarkably well so far, not just at preventing infection but, most important, at preventing serious illness and hospitalization, even as new variants circulate around the globe.

The variants are “all the more reason to get vaccinated,” said Dr. Anthony S. Fauci, the nation’s top infectious disease specialist. “The bottom line is the vaccines we are using very well protect against the most dominant variant we have right now, and to varying degrees protect against serious disease among several of the other variants.”

Part of the confusion stems from what vaccine efficacy really means and the use of terms like “vaccine evasion,” which sounds a lot scarier than it is. In addition, the fact that two vaccines have achieved about 95 percent efficacy has created unrealistic expectations about what it takes for a vaccine to perform well.

Here are answers to common questions about the variants and the vaccines being used to stop Covid-19.

The variant called B.1.1.7, which was first identified in Britain, is now the most common source of new infections in the United States. This highly contagious variant is also fueling the spread of the virus in Europe and has been found in 114 countries. A mutation allows this version of the virus to more effectively attach to cells. Carriers may also shed much higher levels of virus and stay infectious longer.

The main concern about B.1.1.7 is that it is highly infectious and spreads quickly among the unvaccinated, potentially overwhelming hospitals in areas where cases are surging.

All of the major vaccines in use — Pfizer-BioNTech, Moderna, Johnson & Johnson, AstraZeneca, Sputnik and Novavax — have been shown to be effective against B.1.1.7. We know this from a variety of studies and indicators. First, scientists have used the blood of vaccinated patients to study how well vaccine antibodies bind to a variant in a test tube. The vaccines have all performed relatively well against B.1.1.7. There’s also clinical trial data, particularly from Johnson & Johnson and AstraZeneca (which is the most widely used vaccine around the world), that shows they are highly effective against both preventing infection and serious illness in areas where B.1.1.7 is circulating. And in Israel, for instance, where 80 percent of the eligible population is vaccinated (all with the Pfizer shot), case counts are plummeting, even as schools, restaurants and workplaces open up, suggesting that vaccines are tamping down new infections, including those caused by variants.

No vaccine is foolproof, and even though the Covid vaccines are highly protective, sometimes vaccinated people still get infected. But breakthrough cases of vaccinated people are very rare, even as variants are fueling a surge in case counts. And the vaccines clearly prevent severe illness and hospitalization in the few vaccinated patients who do get infected.

So what’s the risk of getting infected after vaccination? Nobody knows for sure, but we have some clues. During the Moderna trial, for instance, only 11 patients out of 15,210 who were vaccinated got infected. Both Pfizer and Moderna now are doing more detailed studies of breakthrough cases among vaccinated trial participants, and should be releasing that data soon.

Two real-world studies of vaccinated health care workers, who have a much higher risk of virus exposure than the rest of us, offer hopeful signs. One study found that just four out of 8,121 fully vaccinated employees at the University of Texas Southwestern Medical Center in Dallas became infected. The other found that only seven out of 14,990 workers at UC San Diego Health and the David Geffen School of Medicine at the University of California, Los Angeles, tested positive two or more weeks after receiving a second dose of either the Pfizer-BioNTech or Moderna vaccines. Both reports were published in the New England Journal of Medicine, and are a sign that even as cases were surging in the United States, breakthrough cases were uncommon, even among individuals who were often exposed to sick patients. Most important, patients who were infected after vaccination had mild symptoms. Some people had no symptoms at all, and were discovered only through testing in studies or as part of their unrelated medical care.

Researchers are still studying whether the variants eventually might increase the number of breakthrough cases or if vaccine antibodies begin to wane over time. So far, data from Moderna show the vaccine still remains 90 percent effective after at least six months. Pfizer has reported similar results.

A recent study of 149 people in Israel who became infected after vaccination with the Pfizer vaccine suggested that a variant first identified in South Africa was more likely to cause breakthrough infections. However, those eight infections occurred between days seven and 13 following the second dose. “We didn’t see any South Africa variant 14 days after the second dose,” said Adi Stern, the study’s senior author, a professor at the Shmunis School of Biomedicine and Cancer Research, Tel Aviv University. “It was a small sample size, but it’s very possible that two weeks after the second dose, maybe the protection level goes up and that blocks the South Africa variant completely. It gives us more room for optimism.”

For now, the variants don’t appear to be increasing the rate of infection in vaccinated people, but that could change as more data are collected. Read more about breakthrough cases here.

The C.D.C. is tracking more than a dozen variants, but only a few qualify as “variants of concern,” which is a public health designation to identify variants that could be more transmissible or have other qualities that make them more of a risk. The main additional variants everyone is talking about right now are the B.1.351, which was first detected in South Africa, and the P.1, which was first identified in Brazil. While there are other variants (including two “California” variants, B.1.427 and B.1.429, and a New York variant, B.1.526) for now, it seems, that the South Africa and Brazil variants (which as of late March together accounted for about 2 percent of cases in the United States) are causing the most concern. While a new variant can emerge at any time, existing variants also compete with each other for dominance. One interesting new development: In countries like the United States where B.1.1.7 is dominant, some of the other variants seem to be getting crowded out, making them less of a worry.

There is a concern that the B.1.351 and the P.1 are better at dodging vaccine antibodies than other variants. But that doesn’t mean the vaccines don’t work at all. It just means the level of protection you get from the vaccines against these variants could be lower than when the shots were studied against early forms of the virus. Among the variants, the B.1.351 may pose the biggest challenge so far. It has a key mutation — called E484K, and often shortened to “Eek” — that can help the virus evade some, but probably not all, antibodies.

Remember that there’s a lot of “cushion” provided by this current crop of vaccines, so even if a vaccine is less effective against a variant, it appears that it’s still going to do a good job of protecting you from serious illness.

We don’t yet have precise estimates of vaccine effectiveness against B.1.351, which may be the most challenging variant so far. But studies show that the various vaccines still lower overall risk for infection and help prevent severe disease. A large study of Johnson & Johnson’s one-dose vaccine in South Africa found it was about 85 percent effective at preventing severe disease, and lowered risk for mild to moderate disease by 64 percent. (Distribution of the Johnson & Johnson vaccine has been paused as health officials investigate safety concerns.) There’s less definitive research for the Pfizer and Moderna vaccines against the variant, but it’s believed that these two-dose vaccines still reduce risk of infection against the variant by about 60 percent to 70 percent and still are highly effective at preventing severe disease and hospitalization.

“From everything we know today, there is still protection from the vaccines against the South Africa variant,” said Dr. Stern.

Part of the problem is that we misinterpret what efficacy really means. When someone hears the term “70 percent efficacy,” for instance, they might wrongly conclude that it means 30 percent of vaccinated people would get sick. That’s not the case. Even if a vaccine loses some ground to a variant, a large portion of people are still protected, and only a fraction of vaccinated people will get infected. Here’s why.

To understand efficacy, consider the data from the Pfizer clinical trials. In the unvaccinated group of 21,728, a total of 162 people got infected. But in the vaccinated group of 21,720, only eight people became infected. That’s what is referred to as 95 percent efficacy. It doesn’t mean that 5 percent of the participants (or 1,086 of them) got sick. It means 95 percent fewer vaccinated people got infected compared to the unvaccinated group.

Now imagine a hypothetical scenario with a vaccine that is 70 percent effective against a more challenging variant. Under the same conditions of the clinical trial, vaccination would still protect 21,672 people in the group, and just 48 vaccinated people — less than one percent — would become infected, compared to 162 in the unvaccinated group. Even though overall efficacy was lower, only a fraction of vaccinated people in this scenario would get infected, most likely with only mild illness.

While far more research is needed to fully understand how variants might dodge some (but not all) vaccine antibodies, public health experts note that an estimate of 50 percent to 70 percent efficacy against a challenging variant would still be considered an adequate level of protection.

“Seventy percent is extremely high,” said Dr. Stern. “Basically what this means is that it’s even more important to get vaccinated. If you have 95 percent efficacy, you can create some form of herd immunity with less people. With 70 percent efficacy, it’s even more important to get vaccinated to protect others.”

Vaccine makers already are working on developing booster shots that will target the variants, but it’s not clear how soon they might be needed. “In time, you’re going to see a recommendation for a booster,” said Dr. Peter J. Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine in Houston. “That booster will elevate everybody’s antibodies and increase durability. The booster will probably be configured to target the South African and Brazil variants.”

Even amid the rise of variants, vaccines will significantly lower your risk for infection and will protect you from serious illness and hospitalization.

People who are vaccinated can socialize, unmasked, with other vaccinated people. While vaccinated people still need to follow local health guidelines about wearing a mask and gathering in groups to protect the unvaccinated, vaccinated people can travel, get their hair and nails done, or go to work without worrying. And vaccinated grandparents can hug their unvaccinated grandchildren. Because there are still some outstanding questions about the risk of vaccinated people carrying the virus, a vaccinated person is still advised to wear a mask in public to protect the unvaccinated — although those guidelines may be updated soon.

“The vaccines protect you, so go get vaccinated — that’s the message,” said Dr. Fauci. “If you’re around other vaccinated people, you shouldn’t worry about it at all. Zero.”