WebMD: Infected, Vaccinated, or Both: How Protected Am I From COVID?

quote:

---

“Because, of course, it's much more risky to get infected with the actual virus, than with the vaccine,” says Daniela Weiskopf, PhD, a researcher at the La Jolla Institute for Immunology in California.

---

quote:

---

The agency’s researchers say if you’ve recovered from a COVID-19 infection or are fully vaccinated, you’re probably in good shape for at least 6 months. That’s why this is the recommended interval for people to consider getting a booster dose.

Even though the protection you get after infection and vaccination is generally strong, it’s not perfect.

---

quote:

---

Getting COVID-19 after you’ve been vaccinated or recovered is still possible. But having some immunity -- whether from infection or vaccination -- really drops the odds of this happening to you. And if you do happen to catch COVID, if your immune system has already gotten a heads up about the virus, your infection is much less likely to be one that lands you in the hospital or morgue.

---

quote:

---

In general, people with cold-like symptoms who tested positive but recovered at home are better protected than people who didn’t get any symptoms. And people who were hospitalized for their infections are better protected over the long term than people with milder infections. Though they may have paid a steep price for that protection: Many hospitalized patients continue to have debilitating symptoms that last for months after they go home.

---

quote:

---

On average, though, protection after infection seems to be comparable to vaccination, at least for a while. Six large studies from different countries have looked into this question, and five of them have used the very sensitive real-time polymerase chain reaction test (RT-PCR) -- the one that has to be sent off and processed in a lab, usually after an uncomfortably long swab is inserted deep into your sinuses --to count people as truly being previously infected. These studies found that for 6 to 9 months after recovery, a person was 80% to 93% less likely to get COVID-19 again.

---

quote:

---

One study of 25,000 health care workers, who were all tested every 2 weeks -- whether they had symptoms or not -- may offer a clearer picture. In this study, health care workers who’d previously tested positive for COVID-19 were 84% less likely to test positive for the virus again. They were 93% less likely to get an infection that made them sick, and 52% less likely to get an infection without symptoms, for at least 6 months after they recovered.

---

quote:

---

It’s not yet known how long the COVID-19 vaccines remain protective. There’s some evidence that protection against symptomatic infections wanes a bit over time as antibody levels drop. But protection against severe illness, including hospitalization and death, has remained high so far, even without a booster.

---

quote:

---

Are Antibodies Different After Infection Compared to Vaccination?
Yes. And researchers don’t yet understand what these differences mean.

It seems to come down to a question of quality versus quantity. Vaccines seem to produce higher peak antibody levels than natural infections do. But these antibodies are highly specialized, able to recognize only the parts of the virus they were designed to target.

“The mRNA vaccine directs all the immune responses to the single spike protein,” says Alice Cho, PhD, who is studying the differences in vaccine and infection-created immunity at The Rockefeller University in New York. “There’s a lot more to respond to with a virus than there is in a vaccine.”

The job of remembering the various pieces and parts of a foreign invader, so that it can be quickly recognized and disarmed should it ever return, falls to immune cells called memory B cells.

Memory B cells, in turn, make plasma cells that then crank out antibodies that are custom tailored to attach to their targets.

Antibody levels gradually fall over a few months’ time as the plasma cells that make them die off. But memory B cells live for extended periods. One study that was attempting to measure the lifespan of individual memory B cells in mice, found that these cells probably live as long as the mouse itself. Memory B cells induced by smallpox vaccination may live at least 60 years -- virtually an entire lifetime.

“Those stay resident in our lymph nodes and primarily in our bone marrow and are called out whenever the body sees that same pathogen again,” Poland says.

Cho’s research team has found that when memory B cells are trained by the vaccine, they become one-hit wonders, cranking out copious amounts of the same kinds of antibodies over and over again.

Memory B cells trained by viral infection, however, are more versatile. They continue to evolve over several months and produce higher quality antibodies that appear to become more potent over time and can even develop activity against future variants.

---

quote:

---

“While a natural infection may induce maturation of antibodies with broader activity than a vaccine does -- a natural infection can also kill you,” says Michel Nussenzweig, MD, PhD, head of Rockefeller’s Laboratory of Molecular Immunology.

Sure, memory B cells generated by infections may be immunological Swiss Army Knives, but maybe, argues Donna Farber, PhD, an immunologist at Columbia University in New York, we really only need a single blade.

“The thing with the vaccine is that it’s really focused,” she says. “It’s not giving you all these other viral proteins. It’s only giving you the spike.”

“It may be even better than the level of neutralizing spike antibodies you’re going to get from the infection,” she says. “With a viral infection, the immune response really has a lot to do. It’s really being distracted by all these other proteins.”

“Whereas with the vaccine, it’s just saying to the immune response, ‘This is the immunity we need,’” Farber says. “‘Just generate this immunity.’ So it’s focusing the immune response in a way that’s going to guarantee that you’re going to get that protective response.”

---