Cleveland, Ohio 2021-06-25 12:38:00 –
About six months ago, on December 11, the Food and Drug Administration approved the first COVID-19 vaccine for emergency use in the United States. Following that was a push developed by Pfizer and BioNTech to provide the shot to high-risk people (SN: 12/1/20). Modena’s jab wasn’t too late. I got an emergency use authorization just one week after Pfizer’s jab (SN: 12/17/20; SN: 12/11/20). And in February 2021, when the FDA approved the Johnson & Johnson injection, there were three COVID-19 vaccines (SN: 2/27/21).
Currently, about 40 percent of the US population is fully vaccinated. Over half of the residents receive at least one dose. Meanwhile, US COVID-19 cases and deaths have plummeted to their lowest levels since March 2020.
Two major questions arise in the ongoing efforts to vaccinate people: Is immune protection against the coronavirus long-lasting? Or do people need booster shots right away?
Kirsten Lyke, a vaccinologist at the University of Maryland School of Medicine in Baltimore, said at this point, “no one knows” if a booster is needed. But researchers are working to understand it.
Here’s what we know about coronavirus immunity and potential booster shots:
Immunity lasts at least 6 months, and in some cases longer.
Whether people need COVID-19 booster shots depends largely on how long the body’s immune response prevents it from becoming a serious illness. So far, researchers say this protection lasts for at least six months, and in some cases even longer.
Much of what scientists now know about long-term immunity comes from what they collect from people infected with the coronavirus. Ali Elbedi, an immunologist at Washington University in St. Louis School of Medicine, says that immunological memory against the virus seems to follow the rules, at least for most people.
That is, after the virus has gained a foothold, the body releases a wave of immune proteins called antibodies, and immune cells are called T cells to fight the virus. Antibodies usually attack the virus itself, but T cells ring additional alarm bells and kill infected cells. Antibodies and T cells work together to defeat the virus and help the immune system form memory of the pathogen, says Ellebedy. Its immunological memory is essential for protection if a person is exposed to the virus again.
Studies reveal evidence that most people develop immunological memory against the coronavirus. Ellebedy, for example, found signs of antibody memory in people who recovered from the infection. People infected with mild COVID-19 had long-lived antibody-producing immune cells in the bone marrow 11 months after infection, he and colleagues reported in Nature on May 24. These cells continue to make antibodies to the virus long after the virus leaves the body, providing protection in the event that a person is exposed again.
Evidence has been built that vaccines provide similar protection. In that case, the booster may not be needed for a while. In the last update from the vaccine developer, “things looked pretty good,” says Like. Researchers reported in April that people who received Moderna shots still had high levels of antibodies six months after receiving the second dose. Pfizer’s jab is 91.3% effective against COVID-19 symptoms six months later, the drug company announced in a news release on April 1.
Still, “I don’t know how any of these COVID-19 vaccines will work for more than a year,” says Lyke. The first test to test whether the vaccine stimulates an immune response has just reached that point, and researchers are following up on participants (SN: 7/21/20).
Coronavirus variants may increase the likelihood of booster shots.
Even if the protection provided by the immune system is long-lasting, viruses like coronavirus are good at avoiding those reactions. Suitable example: The emergence of viral variants that may reduce the effectiveness of the COVID-19 vaccine over the original version of the virus (SN: 5/11/21).
“I don’t think we’ll be discussing boost possibilities,” Ellebedy said without the variant. “So far, vaccines have been found to be very powerful. Why do we need boosters when the virus doesn’t change?”
Available vaccines protect people from the worst COVID-19, even if they are infected with one of the circulating mutants. However, this is not always the case. “Future variants that we are unaware of may come down and surprise us,” says Like. Nevertheless, multiple COVID-19 vaccines are flexible in design and can be easily adapted to tackle new variants (SN: 1/27/21). And that becomes a matter of dose production.
Some companies, including Pfizer and Moderna, are already testing booster shots to combat new variants, especially the first beta variant to emerge in South Africa. Early results from Moderna show that people who receive booster shots using the viral protein version of the beta variant can prevent the variant from infecting cells compared to those who received the original vaccine three times. It suggests that he had a good antibody.
Still, one question is what the best mutant boosters look like, says Jerome Kim, a vaccine scholar and director of the International Vaccine Institute in Seoul, South Korea. Researchers around the world, for example, carefully monitor circulating influenza strains to determine which strains should be included in the flu vaccine. In the future, experts may need to monitor the coronavirus in a similar manner.
Low vaccination rates around the world can also increase the likelihood of booster vaccination.
There are many other countries that are lagging behind in vaccination as countries like the United States are starting to get out of the worst of the pandemic (SN: 2/26/21). This is partly because wealthy countries buy most of the doses available to vaccinate their populations, and low-income countries struggle to fire.
To date, more than 2 billion doses have been administered worldwide. In some countries, including Canada, the United Kingdom, Chile and Israel, about 60 percent of the population receives at least one dose. However, in places like Nigeria and Sierra Leone, only about 1 percent of people have been vaccinated at least once.
Low vaccination rates in many places pose problems for efforts to quell transmissions and end pandemics. Also, the more prevalent the coronavirus, the more opportunities for new variants to emerge and the more likely it is to be a booster shot. “I managed to find a gap, just like any other virus,” says Coronavirus, Kim says. “It is the nature of the virus that finds its weaknesses, and there is another mutant before you know it.”
In some countries, there are visually impaired people due to lack of genetic surveillance. Strengthening its capabilities in regions such as Africa, Latin America, and South Asia will address the diversity of coronaviruses in those locations and capture new variants before they become a global problem. Useful.
It is also important to deliver vaccines where they are needed through efforts such as COVAX, an international initiative to help distribute COVID-19 to low-income countries. “We know that mutants will occur, so we have to start going to places with really bad outbreaks,” Kim says.
“Mix and Match” COVID boosters may offer even more protection.
To prepare for the future when people need COVID-19 boosters, the National Institute of Allergy and Infectious Diseases began clinical trials on June 1 to test the combination and matching of COVID-19 vaccines.
The big question is whether the mixed-and-match vaccine enhances the immune response to the coronavirus, says Like, one of the researchers leading the study. If someone is given an mRNA vaccine like Moderna or Pfizer and then a Johnson & Johnson booster, “Can we increase? [the immune response] By switching platforms? “Like says.
For example, mixing different types of Ebola or HIV vaccines can provoke a stronger immune response than multiple doses of the same vaccine (SN: 6/4/21). The idea is that each shot activates multiple parts of the immune system, says Like. The mRNA vaccine may encourage the body to make many antibodies that attack the virus. Second, doses of vaccines like Johnson & Johnson may induce more T cells using a common cold virus that has been modified to not cause illness. “When combined [the shots]We want to prove that we can make the most of both responses that work synergistically, “says Lyke.
Early results from a similar trial conducted in the United Kingdom suggest that the answer for COVID-19 shots is yes. People who received Pfizer’s 8-week dose following AstraZeneca’s COVID-19 shot showed a strong immune response, researchers said in a preliminary study posted on medRxiv.org on June 1. I reported. The antibodies of people who received two different vaccines were better at recognizing beta-like variants than the antibodies of people who received two doses of Pfizer vaccine.
Another study in Spain found that people who received Pfizer after receiving COVID-19 shots of AstraZeneca had higher levels of antibodies compared to those who received only one AstraZeneca vaccine. understood. However, it is unclear how those levels will be compared to people who took the same shot twice.
One of the advantages of US testing is its flexible design, says Lyke. This means that when a new variant occurs, researchers can add new groups to the test to test the newly developed booster. “When you get the data [about variants] It comes from other countries, so we can really start focusing on what we need to answer as a hole in the data. ”
Originally issued by Science news, A non-profit news room. Reissued here with permission.
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