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Home of Sidney Kimmel Medical College

The Truth About Post-COVID Invulnerability, Vaccine Shedding
and More

Some recovered COVID-19 patients are vaccine-hesitant. Here’s why they shouldn’t be.

According to the Centers for Disease Control and Prevention (CDC), there have been a total of 32,356,034 COVID-19 cases and 576,238 COVID-19 deaths in the United States since the start of the pandemic. That leaves nearly over 31 million survivors – all of whom should get vaccinated if they haven’t already.

As more Americans receive coronavirus vaccines, the percentage who express hesitancy about doing so has decreased, according to a recent CBS News poll. Nevertheless, four in 10 Americans say “maybe” (18%) or “no” outright (22%) when asked if they will get vaccinated.

Among those four in 10 are people who have already had COVID-19. One key reason for this particular group’s hesitancy is that they don’t believe they need to be vaccinated.

They’re incorrect.

“People who’ve had COVID-19 do need to be vaccinated, and there’s absolutely no question about that,” says Dr. John J. Zurlo, division director of Infectious Diseases at Jefferson Health.

The Uncertainty of Immunity

To back this up, Dr. Zurlo cites the recently published results of a longitudinal study conducted among patients in Denmark. Scientists conducted widespread testing among large segments of the Danish population to determine how effective past COVID infection is in preventing future COVID infection.

“They estimated the level of protectiveness to be at about 80% at around one year,” says Dr. Zurlo. “That’s encouraging information, but nonetheless, it leaves 20% of individuals with COVID who could get it again. Happily, we haven’t seen a lot of that yet. The fact is, it hasn’t yet been determined how long immunity lasts, whether from natural infection or from vaccination.”

Dr. Zurlo also notes another significant paper that established that when people are seriously ill with COVID, they get a more robust immunologic response than those who have mild or asymptomatic COVID. Although hospitals were certainly challenged during the past 15 months, a relatively small percentage of patients with COVID-19 were so severely ill that they required hospitalization. Therefore, it’s not at all clear yet how long the immunity for patients who’ve had only a mild case COVID will last.

Post-Vaccination Side Effects

Post-vaccination side effects, such as pain at the inoculation site, low-grade fever and muscle aches – usually following the second dose of the two-dose Pfizer and Moderna vaccines – are common among those who haven’t had COVID-19. But are they worse for those who have had it?

“I think that’s true,” responds Dr. Zurlo. “I haven’t seen any hard data about this, but there’s plenty of anecdotal evidence to suggest that people who have had COVID-19 and get their first vaccine dose have a reaction much like many who haven’t had it experience following their second dose.” Do those who’ve had COVID-19 experience different side effects, such as insomnia, twitching and/or rashes? “I haven’t heard of or seen any study suggesting that that’s true.”

Another concern making its way through social media and more that isn’t true, Dr. Zurlo adds, is that side effects are worse if patients get vaccinated less than 90 days after being diagnosed with COVID-19.

“The CDC’s recommended guideline that people should wait around 90 days after having been diagnosed with COVID-19 to get their vaccine was focused mostly on the fact that at the start of vaccination availability, there was limited vaccine supply,” explains Dr. Zurlo. “So, we wanted those people who’ve had COVID to wait 90 days because they were more likely than others to be immune and didn’t need to be vaccinated that soon. The vaccine supply needed to be preserved for those less likely to be immune. But now, we have plenty of vaccines, so people who’ve had COVID and have recovered can get vaccinated whenever they wish.”

The Truth About Vaccine Shedding

Most vaccines are designed around the notion of a spike protein. It’s called that because if you look at a blowup of the virus, you’ll see a little spike or bunch of spikes protruding off the edge of this round virus. The spike protein is integral in the pathogenesis, or function, of the virus. Creation of antibodies to block this protein protect against infection – that’s essentially how vaccines work.

“When the spike protein is presented to our immune system, we develop an entire immune response that includes antibodies that bind to the spike protein,” explains Dr. Zurlo. “Once we’re fully immunized and we have these antibodies floating in our bloodstream, if the virus comes our way and gets into our system, the antibodies will block the spike protein and keep it from attaching to our cells and causing disease. That, in essence, is how vaccines work. There are also immune cells in addition to antibodies that also work against the virus.”

The latest anti-vax myth is about “vaccine shedding” – the notion that people who’ve had the vaccine can somehow shed the spike protein. That, in turn, according to this myth, can cause menstrual cycle irregularities, miscarriages, and sterility in other women just by being in close proximity to them.

“There’s not a shred of evidence to support any of that, period!” says Dr. Zurlo.

How Long Do Antibodies Last?

Given that antibodies prevent illness, it’s natural to wonder how long someone has them after recovering from COVID-19.

“Based on the Danish study I referenced earlier, as well as a more recent study of military personnel who’ve had COVID, we have really excellent reason to think antibodies last at least six months,” replies Dr. Zurlo. “In fact, in a few well-done studies, they last at least 12 months. It’s possible they could last a lifetime – we just simply don’t know, as we haven’t had experience with COVID-19 or vaccines long enough. We do know that the presence of antibodies correlates with immunity, but that’s not likely to be the whole story.”

In fact, according to Dr. Zurlo, it’s likely not to be the whole story. It’s possible, as we’ve seen in other types of infection, that even when the antibodies drop to a level that we can’t even measure, it doesn’t necessarily mean that they’re not there, or that they would not quickly build up if an individual were exposed to that same infection again. As mentioned, there are immune cells in addition to antibodies that also play a role.  In the end, it’s really going to be about the epidemiologic studies of people who’ve had COVID-19 and then get it again and correlating their blood studies (including their antibody levels) that really will tell the tale.

Need a Boost?

Something those who’ve been vaccinated wonders is, “Will I need a booster? If so, how often? Will I need it yearly, like with influenza? Maybe every five years?”

“These answers are not currently obvious or available,” responds Dr. Zurlo. “The vaccine companies are preparing for the possibility that people will need boosters, perhaps in November or December, but we don’t know that yet.”

The Bottom Line: Get Vaccinated!

Dr. Zurlo emphasizes, “My team and I have been treating COVID-19 patients over the last 15 months of the pandemic, and we’ve produced a document of treatment guidelines that’s updated constantly. It goes through names of medications and treatment algorithms that the public has heard on television, like dexamethasone, remdesivir, monoclonal antibodies and convalescent plasma. We employ these modalities as best we know how based on the science. But they all pale in comparison to the effectiveness of these vaccines which have been 75-95% effective in preventing COVID and nearly 100% effective in presenting severe COVID. They’ve been given to tens of millions of people, and we’ve rarely seen serious side effects. Vaccinations really work, they are really safe, and there’s no reason not to be vaccinated!”

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COVID-19, From the Experts