What You Know About Covid-19 Immunity-And What Does It Mean for Vaccine Boosters |

Since the beginning of the pandemic, scientists have sought to better understand immunity to the new coronavirus. How immunized is a person after being vaccinated with Covid-19, after being vaccinated, or both? And what does long-term immunity mean for booster shots?

It’s too early to tell, but experts are approaching deciphering the code.

Current wisdom about potential coronavirus vaccine boosters suggests that they may be needed someday-but exactly when it is unknown, at the U.S. Food and Drug Administration’s Biopharmaceutical Evaluation Research Center. The director, Dr. Peter Marks, Said on thursday Between Covid-19 Vaccine Education and Equity Project Webinar..

“We need to see where this interacts. Is it possible that we need a booster at some point? Yes. Is it possible? Yes. Do you know the exact time? No,” Marks said. He said. “But if you have to see a crystal ball, for the average adult, it’s faster than a year after vaccination, and hopefully it won’t.”

And experts emphasize that anyone who is currently fully vaccinated should be protected. But the reason the potential booster timeline remains unclear is that scientists collect data on how long the immunity to Covid-19 will last in the future and how to take into account future mutations. I still need time to do it.

When a person hasImmunity, “In general, that means they have protection against illness. Active immunization can be obtained by either vaccination or infection. Your immune system develops antibodies that are induced by vaccination or in response to infection-and both immune responses can be maintained in “memory.”

Immunity is often measured by the presence of antibodies- Protein made by the immune system To help fight infections in the blood. They can usually be determined by laboratory tests. But the immune system is more than just an antibody.They involve many players, including B cells, Produce antibodies,and T cells, Target infected cells.

Studies show that both antibodies and T cells May recognize infections from variants Pathogens, such as the new coronavirus variants in circulation today, are similar enough to be recognized by the memory of the immune system, despite important differences that may spread them more easily. Have sex.

And even if someone recovers from a previous infection and has innate immunity, vaccination can help boost their immune memory.

Vaccine maker to monitor immunity

Currently, three coronavirus vaccines are licensed for emergency use in the United States. A two-dose Pfizer / BioNTech vaccine for ages 12 and older. Two-dose Moderna vaccine for ages 18 and older. Single dose of Johnson & Johnson vaccine over 18 years old.

All three companies are investigating the potential use of boosters.

Vaccine makers also protect against long-term (eg, perhaps after a year or more) reduction in immunity elicited by these vaccines, and from coronavirus variants that may emerge and evolve. I am studying whether or not.

If so, vaccinated individuals may need booster doses of vaccine to remain protected from the original coronavirus strain and newly emerging variants-every 10 years. Similar to the method recommended for tetanus boosters, or different flu vaccines are recommended each year.

For other viruses Measles usually leaves someone immune For life.The same was true for smallpox, before that The virus was eradicated in the 1970s By a global vaccination campaign. Proper vaccination against measles and smallpox will completely prevent infection.

However, be careful with respiratory viruses such as influenza and coronavirus. People can get the flu many times, and flu vaccines usually provide only partial protection against infection and serious illness because multiple flu viruses are circulating due to mutations. ..However, for coronavirus Slower mutation rate than influenza..

Still, doctors are worried that the coronavirus may become like the flu. Influenza requires a new vaccine every year due to the rapid mutation of circulating strains and the rapid weakening of the vaccine’s immunity.

In the case of the coronavirus vaccine, several studies have evaluated the immune response elicited by the modelna and Pfizer vaccines against the original strain of the virus compared to the mutant. “These studies observed that the mutants had no moderate defects or defects in cell-mediated immune recognition,” he said. US Centers for Disease Control and Prevention website, Updated on Thursday.

“Therefore, cell-mediated immunity may help limit the severity of infections caused by mutants that partially escape neutralizing antibodies,” said the CDC.

Although it is difficult to predict how reduced neutralizing activity will affect the efficacy of the Covid-19 vaccine, the overall study found that antibody neutralizing activity was found in fully vaccinated people. Generally expensive Than what was observed among those who recovered from Covid-19.

According to clinical trial data, the protective effect provided by the Pfizer and Modena coronavirus vaccines can last at least 9 months. FDA Mark said in April.. However, experts are struggling to point out that immunity does not stop in nine months. This means that the longest volunteers in the trial were followed to see what their immunity was and collect data.

Immunity can last much longer. Researchers just need time to evaluate.

The medical community still needs data to determine how immunity can decline over time, Dr. AmeshAdalja, Johns Hopkins Center for Health Security Those who weren’t involved in the study told CNN by email Thursday.

The degree can be measured as to whether fully vaccinated people will eventually suffer from a higher proportion of breakthrough infections or severe infections that require hospitalization.

“For me, that’s the limit,” Adalja said.

On the other hand, studies of innate immunity due to previous coronavirus infections are proceeding somewhat longer than vaccine trials.

Latest findings on long-term immunity

Two new studies this week add to the growing evidence suggesting that innate immunity to coronavirus may be long-lasting after someone recovers from Covid-19-perhaps at least a year. But that doesn’t mean they shouldn’t be vaccinated. Nor does it mean that immunity lasts forever.

A study, Published in Journal Nature On Monday, it was discovered that the immune cells in the bone marrow of people infected with the coronavirus have a long-lived “memory” of the infection.

Other studies, Published in the journal EClinical Medicine On Monday, the Covid-19 antibody was found to remain detectable among recovered people for approximately 10 months after infection.

Bone marrow cells can retain Covid-19 memory for at least 11 months after someone is infected. These cells are the “essential” source of protective antibodies, according to a new study published in Nature.

Researchers at Washington University in St. Louis examined blood samples from 77 people previously infected with SARS-CoV-2, the virus that causes Covid-19. Researchers found the first reduction in the presence of Covid-19 antibody after infection, but the reduction slowed between 4 and 11 months.

The researchers also examined bone marrow samples taken from 19 previously infected patients about 7 and 11 months after infection. Researchers found the Covid-19 antibody in 15 of 19 patients. Unlike the observed reduction of other antibodies, the antibodies produced by the cells of the bone marrow appeared to remain stable.

“The good news is that these antibodies are produced and maintained,” said the author of the study. Washington University in St. Louis, Told CNN’s John Berman on Thursday.

However, he added, the findings do not suggest that people with Covid-19 no longer need to be vaccinated. Rather, vaccination may further enhance the natural immune response.

“I think vaccination is a big motivation because people who have been infected and have produced this beautiful memory for a long time can put these memory cells into action,” Elbedi said. He added that having does not mean a person. It is completely protected.

“Our data explain why people who experienced a mild SARS-CoV-2 infection last year are producing such a wonderful response to vaccination. It is the strong that they developed after infection. It’s for good immunological memory, “Ellebedy told CNN in an email Thursday.

“But not all previously infected people are the same,” he added. “For a variety of reasons, some people do not generate a strong immune response to the infection even after they have survived the infection. Therefore, it is best for people who have been vaccinated twice to receive both vaccinations.” ..

For the same reason (whether due to age or immunodeficiency), some people are advised to follow a different booster schedule in the future when booster shots are ultimately needed.

Nine out of ten people infected with the coronavirus develop innate immunity to the virus, which “persists with little decay” from the first infection to 10 months, researchers at the National Laboratory Labcorp conducted. EClinical Medicine research suggests.

Researchers found that approximately 90% of recovered Covid-19 patients tested in this study had detectable antibodies by 21 days after infection.

Researchers analyzed data from 39,086 people confirmed to have Covid-19 between March 2020 and January 2021, and at least in Labcorp after being positive for coronavirus infection. One antibody test was performed.

The data did not include patient demographics or information on the severity of certain Covid-19 cases.

“We need to do more research to understand that antibody types and levels suggest protection from reinfection,” said Dr. Brian Caveney, Chief Medical Officer and President of Labcorp Diagnostics. .. Said in the news release on Monday. “But the long-term presence of certain antibodies is a promising sign as we continue to think about their safe emergence from the pandemic, future vaccinations, and the timing of booster shots.”

CNN’s Maggie Fox, Ryan Prior and Naomi Thomas contributed to this report.