COVID Reinfection Rates, Antibodies, Vaccines: What We Know


COVID Reinfection Rates, Antibodies, Vaccines: What We Know

The new normal is now.

In what seemed like an instant, COVID-19 became an unavoidable aspect of everyday life more than two years ago – with no sign that we’ll ever see anything else again.

As we look ahead to our future lives with waves of new variants and “stealthy” subvariants and seasonal vaccine boosters to match, the question arises: should we fear reinfection?

Doctors have recently confirmed that those infected with an earlier Omicron variant, which first emerged last summer and has spread rapidly, can indeed test positive for the new subvariant again.

Last week, as the newest strain — BA.2 or BA2.12.1 — announced its presence in New York City and clusters in the Northeast and Midwest, the US passed a somber milestone: 1,000,000 COVID deaths. Worldwide we have lost more than 6,000,000.

The Post spoke to NYU Langone Health infectious disease expert Dr. Michael Phillips on what to expect from life with COVID as we know it.

Can you catch COVID twice – and who is at risk?

There is no such thing as perfect immunity to COVID. Regardless of severity or vaccination, someone who tests positive for the virus can eventually become infected again.

“Our hospitalizations have increased over the past few weeks, particularly with this newer variant of Omicron,” said Dr. Phillips to The Post. “But fortunately the vast majority of people [who] The infection tends to recover without too much trouble.”

But for some, the stakes are higher. Individuals who have not received two doses of the mRNA vaccine and individuals with compromised immune systems due to age, medications, pre-existing illnesses, or other clinical factors such as B. poor physical fitness, have a higher risk of re-infection and severe illness with COVID-19.

But Phillips warns against “developing[ing] a laissez-faire attitude about it.” While some relatively young, healthy, and vaccinated individuals can be re-infected with just a mild case, the person they pass it on to – possibly someone with a compromised immune system due to age, medications, pre-existing disease or other clinical factors such as B. Poor physical condition Fitness – maybe not so good.

Omicron is “very, very different from previous waves of Delta,” Phillips added. “I think it certainly changed our game plan.” Now more than ever, the focus of prevention efforts is on protecting those who are at greater risk of serious illness — and protecting yourself from COVID reinfection also means “protecting.”[ing] the vulnerable.”

Can you be reinfected with the same COVID variant?

It is certainly possible, especially in those who are unvaccinated. Unlike previous variants, Omicron has rapidly evolved into multiple subtypes, resulting in simultaneous localized eruptions. In the meantime, there’s no telling how many positive cases of COVID-19 go unreported, whether due to a lack of testing or symptoms warranting an alert. So whether you have to fear reinfection with the same niche strain is perhaps not a pragmatic question – because by the time it is answered, a new strain could already be here.

“There are so many of these other variants within this big family of coronaviruses, and we typically get three to four infections a year,” Phillips explained, most of which present as the common cold.

Ideally, SARS-CoV-2 could disappear into the darkness of the coronavirus like many others — but we’re not there yet, and it’s too early to tell if that’s a viable prospect. “It’s still so tough that we have to be pretty careful,” Phillips said. “We just don’t know enough about future variants yet to lower our vigilance.”

COVID Alert Flyer
New York City residents are on “high alert” as of Monday, May 18, 2022.
New York Department of Health and Mental Hygiene

How long after contracting COVID can you become infected again?

This is another complicated question – especially for patients with long COVID who appear to have low, even undetectable levels of virus for weeks and months. For mild to moderate cases, people who test positive for COVID can expect their infection to clear up within five to 10 days of the onset of their symptoms or since their confirmed test result.

New research suggests the average immune system can fight off a COVID reinfection three to five months after the previous bout. Because of this, according to the Centers for Disease Control and Prevention, people who have had a confirmed infection within the past 90 days are not expected to quarantine after contact with another infected person.

But about six months later, all bets are off when antibodies are known to wane — regardless of the vaccine.

How long do COVID antibodies last?

Experts don’t know for sure. While those who survive COVID appear to be largely protected from repeat or severe illness up to five months after the previous infection, there is not yet enough data available to be sure how long these COVID-specific antibodies linger, or this even confirming the presence of antibodies guarantees immunity, according to the Food and Drug Administration.

B cells of the immune system produce COVID-specific antibodies designed to attack the virus immediately before it can enter tissue cells and multiply. They begin to form within the first few days of infection or vaccination and continue to build for several weeks until they peak about three months after — when your COVID defenses are at their strongest.

The good news is that waning antibodies doesn’t mean we’re completely defenseless, as some B cells will remember the tools they previously needed to build COVID antibodies during reinvasion. (Boosters also help our immune system remember how to fight.) Meanwhile, our killer T cells, the immune system’s backup line of defense, may not be as good at preventing the virus from entering the body , but they can recognize an infected host cell — and destroy it before it multiplies into another cell. And while they’re harder to track, they appear to be more reliable than volatile antibodies.

“These seem to remain much more robust,” Phillips said, adding that “in the long run, the T-cell response is likely more important in responding to viral infections.”

Are COVID vaccines still effective?

“We don’t have to be paranoid when a new tribe emerges… but we do have to be thoughtful and prepared for it.”

dr Michael Phillips, MD, NYU Langone Health

More or less. Vaccines remain the best way to build antibodies, the body’s primary line of defense against severe COVID-19 disease. Even if you get infected, you can produce antibodies, but it’s not worth the risk.

“I’m strong for a vaccine because of the problems that come with not getting it,” said Phillips, who also hinted at alternative forms of vaccine technology on the horizon.

Regardless of type, antibodies are known to decline about six months after the last infection or booster shot, making reinfection more likely.

How often can you get a COVID refresher?

For those treated with two doses, a second round should be completed about six weeks after the first. However, it has been well over a year since the vaccine was launched, meaning many patients will have completed these two rounds as early as 2021.

Doctors anticipate that even seasonally redesigned boosters against COVID-19 could become the norm — similar to flu, only different and more troubling: Only one or two major strains emerge globally in a flu season, giving researchers time to prepare vaccines . “It’s not that kind of constant change throughout a ‘season,'” Phillips said, like COVID-19 has done.

Currently, only those with compromised immune systems and those age 50 and older are recommended by the CDC for a third shot — which is a good sign overall.

Phillips said, “We don’t have to be paranoid about the emergence of a new strain…but we do have to be thoughtful and prepared for it.”

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