Was there Covid-19 infection? You may still benefit from a vaccine.

In the United States, 17 million cases of Covid-19 have been reported – about 5 percent of the population. Millions more are infected and have not been tested or had any symptoms at first.

Vaccinations are progressing gradually – first to face-to-face health care and high-risk people, and next, perhaps to other essential workers, followed by people aged 65 and over and those with preexisting conditions.

But it is reasonable to ask, given that there are over 100 million people in these groups and that there are not nearly enough vaccines for them immediately: Should people who have received Covid – 19 get the vaccine too?

After all, the body sets up an immune response to the virus at the time of infection. In laboratory studies, scientists have found that most people who get the virus develop antibodies neutral to it. These antibodies are proteins of the immune system that bind to viruses and make them harmless.

So a person who has contracted the virus has improved his level of immunity. However, immunologists and vaccine experts say that these people can – and perhaps should – at least get vaccinated, if they have a vaccine.

“If I had Covid, personally, I would still like to be vaccinated,” says Alexander Sette, a psychologist at the La Jolla Institute of Immunology.

He and other vaccine and vaccine experts can explain why.

Why people who have received Covid-19 should still be vaccinated

The main reason that everyone – whether they have had Covid-19 before or not – should be vaccinated is because different immune systems have treated the virus differently.

In general, Sette says, an organization will put up a steady immune response. “In fact, we’ve seen it last up to eight months,” he says. But this is only true for 90 percent of people. “For 10 per cent of people, they don’t seem to have a good immune response eight months out.”

Some documented cases have been redefined, which shows that, in some people, the immunity resulting from an initial infection is either weakened or declines over time (scientists do not yet know the prevalence of reinterpretation). In general, scientists have told us that the worse the first infection, the stronger the immune response.

The thing is, “we have no way of telling,” he says, at least easily and competently, if a former person is infectious in the 90 percent or 10 percent. It’s not about taking care as a mask and social distance, or avoiding vaccines after an infection, he said, like “driving a car where you’re 90 percent sure the brakes are a car. ”

This has been the story of the pandemic as a whole: The human body’s response to the SARS-CoV-2 virus that causes Covid-19 has been highly variable. Some people do not get symptoms at all. Some people die from the disease. “Some develop very high levels of antibodies and appear to be in need of vaccines, while others develop unstable levels of antibodies,” the researcher says immunobiology Yale Akiko Iwasaki explains in an email.

So, simple: Vaccination helps to reverse that variability. People who did not give their immune systems a strong response can give up those who did. According to Sette, there is less variability in human immune responses to the Covid-19 vaccines than there is to natural diseases.

And, again, individuals who have received Covid-19 cannot measure their own levels of immunity. Yes, a person could have an antibody test, to see if there are any in their bloodstream.

But there are many, many other components in the immune system, from memory cells B that can be activated to produce antibodies in the future, to T cells, which kill and destroy infectious cells. They are not commonly tested. And even though a person may be diagnosed for all aspects of an immune response to SARS-CoV-2, it is still difficult to know what it means for a second infection. Scientists still do not understand the “protective relationship” for Covid-19. That is: What is the right combination of immune system cells for a particular person to stop them from becoming infected again?

Sette says it is a “reasonable argument” to suggest that people who have received Covid-19 should not be given priority for the vaccine, if stocks remain limited in the long run. -time. But in practice, that argument could be problematic.

For one: “Pre-vaccination testing is too difficult,” Peter Hotez, a vaccination expert and dean of Baylor College’s National School of Tropical Medicine, says in an email. Determining who would be a difficult task perhaps be immune to SARS-CoV-2 prior to vaccination. This can be very difficult to determine who has been there before the vaccination as well.

In addition, again, the information derived from such tests may not be useful in determining a person ‘s permanent immunity.

Vaccines are safe – regardless of whether you have contracted the infection

Overall: “To be safe, I recommend getting vaccinated, even after you get past COVID, when the vaccines are available enough,” Iwasaki says.

It is still a bit unclear what the vaccine would look like in addition to a person’s natural immune response to the disease. Would a person who gave a weak immune response to a natural disease a stronger immune response to a vaccine? It is possible.

“When you are naturally exposed to SARS-CoV-2, there are a number of factors that inhibit a strong immune response,” Iwasaki says. “The exposure dose may be too small. The virus suppresses our immune system (both textured and mutated) to prevent the proper entry of antibody. ”

On the other hand, she says, “vaccines are formulated to give the right dose” of the viral protein, and there is no live virus to suppress immune systems. “There seems to be a much higher and higher level of antibodies generated by vaccines,” she says.

For now, the Centers for Disease Control and Prevention is not making an official recommendation on whether people who have received Covid-19 should be vaccinated; it is awaiting the views of the Vaccine Practice Advisory Committee, a group of medical and public health advisers who make recommendations on their immunization. Although we know from clinical trial data, and a Food and Drug Administration review, that the Pfizer / BioNTech and Moderna vaccines appear to be relatively safe for the general public.

But have they been proven safe, especially for people who are already infected? There may not yet be enough data to say that for sure. “I think the answer may be yes, but we won’t know for sure until the numbers get bigger,” Washington University immunologist and physician Helen Y. Chu wrote in an email. “For most stage 3 tests, there was no pre-existing antibody screening.”

Keep in mind that a lack of safety data for this particular group does not mean it is dangerous. As Chu explained, there just needs to be more data. (On Thursday, Moderna vaccine scientist Jacqueline Miller told the FDA advisory committee that the company is “expecting data in the coming weeks” on how and how the company’s vaccine strengthens human immune systems. previously infected.)

Also unclear from current data: does the vaccine actually elicit a weak immune response to a natural disease – that is, people who have not made enough cells of the immune system to fight against the virus or whether their immune system has fought off the virus has declined over time – an immune boom.

“This hasn’t been answered yet, but I’d say it probably doesn’t hurt,” says Chu. “The antibody declines over time, and the vaccine is likely to boost your previous antibody titles. ”

That said, according to current test data, both vaccines are approximately 95 percent effective in preventing Covid-19. Sette states that a high level of efficacy appears to indicate that the vaccine can produce a strong immune response in most people.

The language of vaccine science is very complex. To say that a vaccine does not protect against a disease is the same as to say that the vaccine makes a person completely immune (or unable to spread the virus). Some people may still have the infection but clear the infection before symptoms appear. Scientists need more data about this fine difference. That said, “it would be hard to say that the vaccine gives you 95 percent protection without stimulating an immune response,” Sette says.

There is a lot about making decisions through the pandemic that has been very difficult. Deciding whether and how to visit friends and loved ones leads to a tedious risk-benefit study. Fortunately, with the vaccines, this decision matrix is ​​much simpler: Even if you have had Covid-19 before, vaccination may help prevent future infections. Yes, more data is needed to be absolutely certain about this. But for now, this is all very encouraging.