Should you get a second COVID-19 booster shot?

The US Food and Drug Administration (FDA) approved second booster doses of Pfizer-BioNTech and Moderna’s COVID-19 vaccines last week. Individuals aged 50 and up, as well as certain immunocompromised adults aged 12 and up, are eligible for this authorization.

Second-stage boosters are “particularly crucial for people 65 and older, as well as those 50 and older with underlying medical disorders that enhance their risk of severe disease from COVID-19,” according to Dr. Rochelle P. Walensky, director of the Centers for Disease Control and Prevention (CDC).

Is it worth it to seek out a second booster immediately if you qualify for one? Are there any drawbacks to receiving the shot right now?

According to John P. Moore, a professor of microbiology and immunology at Weill Cornell Medicine, “there is a general consensus that extra boosters are safe and that those aged 65 and older, as well as immunocompromised people of all ages, would benefit most from a second booster shot.”

“I think where there’s differences of opinion is for healthy people in their 50s,”

Moore said

Moore stated, “I think where there are differences of view is for healthy people in their 50s.”

Moore highlighted that he is not a doctor and hence cannot provide medical advice, but he believes that healthy people in their 50s can get the extra boost now if they want it, but it is not a top priority for them.

If it’s been at least four months since their initial booster dosage of any authorized or approved COVID-19 vaccine, anyone 50 and older can receive a second booster dose of either mRNA vaccine—Pfizer-BioNTech or Moderna—according to the FDA.

If they have disorders that limit their immune response, younger people (those over the age of 12 for the Pfizer-BioNTech vaccination and those over the age of 18 for the Moderna vaccine) can have a second booster dose.

According to the FDA, “These include patients who have had solid organ transplantation,” which requires immunosuppressive medicine, “or who are living with illnesses that are judged to have an equal level of immunocompromise.”

Several studies completed in Israel were used by the FDA to justify the approval of second booster doses.

More than a million participants aged 60 and up who had gotten one or two booster shots were included in one study, which was published on the preprint database medRxiv on Feb. 1. According to Eric Topol, a professor of molecular medicine at Scripps Research in La Jolla, California, the follow-up time was quite short—only 12 days—but it revealed that the rate of serious disease was nearly four times lower in the double-boosted group.

Another study from Israel, published on March 24 in Nature’s preprint database, looked at over 560,000 people aged 60 and up and found that those who got a second booster had a 78 percent lower death rate from COVID-19 than those who just got one booster.

But it’s unclear how long this improvement in protection will endure.

“The deficit in our knowledge base is the lack of follow-up for better protection against severe disease, hospitalization, and mortality,” Topol said in his blog.

We should know how long the heightened protection lasts when these people are followed throughout time, and more data on younger people should be available soon, he added.

According to the FDA, the existing data suggests that second booster doses pose no significant safety risks.

The Israeli Ministry of Health submitted to the FDA a summary of safety surveillance data obtained from about 700,000 patients, predominantly over the age of 60, who got second booster doses of the Pfizer-BioNTech vaccine at least four months after their first booster doses. The FDA stated that this investigation “uncovered no new safety concerns.”

The FDA stated that the Moderna second booster’s safety was “influenced by experience with the Pfizer-BioNTech COVID-19 vaccination and safety information disclosed from independently conducted research.” This tiny trial included 120 adult participants who received a first booster dose of Pfizer-BioNTech and, subsequently, a second booster dose of Moderna. The FDA added that “no additional safety issues were recorded over up to three weeks of follow-up following the second booster dose.”

Who should receive the booster immediately and who can wait?

In terms of who should get the shot now, Topol wrote on his blog that if it’s been more than 4 to 6 months since your last booster dose, he would recommend a second booster. You are over the age of 50, you tolerated the previous shots well, and you are concerned about the BA.2 wave where you live, or that it is gaining legs as you consider your options. Also, if you are going or have plans, that would place you in jeopardy. ” (BA.2 is a subvariant of the omicron that spreads more easily than the original omicron, known as BA.1.)

Topol said that it’s understandable for some eligible people to postpone taking a second booster. For example, he stated that it is “good to wait if there is a low amount of viruses spreading where you live and work.” The CDC’s COVID Data Tracker can be used to monitor the case positivity rate in your county or state; the tracker also indicates the number of new COVID-19 cases, hospital admissions, and deaths.

What about individuals who had a breakthrough omicron case? Topol said that for those who have had three doses of an mRNA vaccination and an omicron infection, there is no need for a second booster right now.

Is it worth waiting for an OMICRON-SPECIFIC booster?

So far, the evidence suggests that you should not wait for an omicron-specific booster.

Researchers have been researching variant-specific boosters in mice and rhesus macaques, a species of primate. According to Moore, animals in these tests were exposed to the omicron variation after being supplemented with either another dose of one of the original mRNA vaccinations or the new, omicron-specific injection. The omicron-specific boosters provided the same level of immunity as the original vaccination formulations.

Moore told Live Science that the variations were “subtle to insignificant.”

However, because these trials were conducted on animals, it needs to be seen whether an omicron-specific booster may provide people with any additional benefit over a standard booster, according to Topol. Human trials of such boosters are currently underway.

Will future shots be less effective? NOW THAT BOOSTERS ARE USED,

Some people may be concerned that receiving a second booster against the original strain of SARS-CoV-2 could undermine their immune system’s efforts to combat future coronavirus strains. There is currently no evidence that getting numerous booster doses of the same variation has this undermining impact.

Some researchers have expressed concern about a process known as “original antigenic sin,” in which the immune system’s initial encounter with a pathogen, whether by infection or vaccination, leaves a persistent “imprint” that affects the immune response to similar germs in the future. Live Science previously reported that a first interaction with an influenza virus as a youngster can influence how well the immune system responds to subsequent flu infections or the yearly flu shot. 

Could original antigenic sin, also known as “immune imprinting” or “antigen imprinting,” influence how the immune system reacts to later SARS-CoV-2 variants and variant-specific boosters?Although studies suggest that a person’s first COVID-19 infection or vaccine does leave an imprint on the immune system, it is unknown if this impairs the immune response to future variations or boosters.

Moore stated, “I’m not convinced that original antigenic sin is an issue here.”

Fortunately, even though current vaccinations train the immune system to respond strongly to the original SARS-CoV-2 variation, they nevertheless produce a spectrum of antibodies that can latch onto numerous types. In comparison, antibody responses to spontaneous infection are far more restricted, according to a study published in the journal Cell on January 24.

There is a possibility that a new variety will emerge that effectively bypasses the first generation of vaccine-induced protection. However, in that situation, antigen imprinting may be less of a concern.

“My own belief is that if a variety comes along that is horrible enough to show significant immune evasion, that very quality will make it something that a new vaccine booster is likely to be able to target advantageously,” drug discovery scientist Derek Lowe said in Science Magazine’s In The Pipeline blog. In other words, a version that resembles the original SARS-CoV-2 may be easier to eradicate with a new, specially engineered booster.

“Omicron, on the other hand, isn’t it,” he wrote. It’s different enough to spread substantially faster, but similar enough for current vaccines to still provide a significant level of protection.

Will a third booster be required soon?

No one knows if or when the FDA will permit a third booster dose for people who have already received two.

Early trials of omicron-specific boosters are still ongoing, so it is unclear whether they will provide an advantage over first-generation boosters. While we wait for the outcomes of those trials, more information about the benefits of second booster doses in different populations should become available.

Recent research suggests that, in general, the second booster dose may not provide as dramatic an increase in antibodies or as big an increase in immunological memory as the first booster dose. In general, this could imply that repeated booster doses may result in “diminishing outcomes.” The New York Times reported.

Based on what we’ve learned thus far, the third dose is likely to be the most crucial, “Moore said, referring to the initial mRNA booster. According to Nature, this first booster comes after a critical period in which the immune system consolidates its memory of the virus and develops immune cell training camps known as “germinal centers.” The booster most likely aids in the consolidation of this immunological memory while also widening the properties of the virus that may be detected by the immune system.

So, will a third booster ever be required? For the time being, we don’t know—and, of course, the introduction of a new SARS-CoV-2 variety could complicate matters.

This article was originally published on Live Science.

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