What is currently known about innate immunity to COVID-19

Much of the recent debate about COVID-19 has focused on those who have been vaccinated and those who have not, but less talk about those who have acquired innate immunity from a viral infection. Hmm.

Previous infections with SARS-CoV-2, the virus that causes COVID-19, appear to provide some immunity to reinfection, but there is ongoing debate about its amount and duration.

Dr. Liam Sullivan, a Grand Rapids infectious disease specialist at Spectrum Health, said innate immunity “provides fairly good protection. There is no doubt about it.” “The question is how long that protection will last. I think it’s too early to say.”

Still, medical experts strongly recommend that people with COVID-19 be vaccinated, with little downside to protecting against recurrent attacks of the virus, and increasing evidence. ..

The following is the latest research on innate immune viruses.

An estimated 28% of Michigan residents have COVID-19 antibodies that indicate a previous infection.

It is based on the results of 1,352 antigen tests conducted in Michigan during the last two weeks of July, according to the US Centers for Disease Control and Prevention.

An estimated July estimate is that 28.1% of Michigan’s population has antibodies, up from 18.9% at the end of February 2021, just before the Michigan spring surge.

The CDC estimates that 34% of Michigan residents under the age of 18 have been infected with the virus so far, based on the results of the antigen in July 2021. 31% of 18-49 years old. 24% aged 50-64 and 17% aged 65 and over.

To date, an estimated 2.8 million Michigans have been infected with the virus, which is about three times the number of confirmed cases, according to the latest data.

Natural infections appear to be strong against delta mutants.

NS New study from Israel Innate immunity suggests that it may be more protective against delta mutants than a double dose of Pfizer vaccine. The study compared 16,125 Israelis vaccinated in January or February with 16,125 infected with SARS-CoV-2 in between, with a breakthrough from June 1 to August 14. We examined the number of typical cases and reinfections.

The study found 238 breakthrough cases, 1.5% of the vaccinated group. On the other hand, among the unvaccinated people, there were 19 reinfections, 0.12% of the group.

An Israeli study also looked at unvaccinated people infected in 2020 and found that they had a higher reinfection rate than recently infected people, but the reinfection rate remains a breakthrough for vaccinated people. It was below the case rate.

At the beginning of this summer Cleveland Clinic Employee studies were published, but no reinfection was seen in unvaccinated workers previously infected with SARS-CoV-2. The study concluded that previous infections appeared to provide protection similar to vaccination.

However, its immunity varies considerably from strain to strain.

According to an Israeli study, infection with the original strain seems to prevent deltas that occurred in India, but reinfections associated with strains that occurred in South Africa and Brazil are increasing.

In the P.1 strain originating in Brazil, One study The efficacy of the antibody was found to be 6-fold weaker than P.1 compared to the original SARS-CoV-2 strain. The study estimated that 25% to 61% of previously infected patients were susceptible to P.1 infection.

A similar problem has been found in a South African variant, also known as B.1.351. NS Novavax vaccine trial Participants in the previously infected control group found that they were as likely to get sick with B.1.351 as participants without natural antibodies, and older strains of COVID-19 were immune to B.1.351. Suggests that we could not provide. By comparison, the vaccine provided some protection.

Vaccines appear to be more consistent in the handling of mutant strains.

According to a study published in June, there are some important differences between immunity acquired through the mRNA vaccine and innate immunity, and the vaccine provides more consistent protection against various mutations in COVID-19. It suggests that there is a possibility of doing so. National Institute of Health..

The study paid particular attention to Receptor binding domain (RBD), An important region of peplomer on the outer surface of SARS-CoV-2. “Antibodies produced by the mRNA vaccine focused on RBD compared to infection-induced antibodies, which more often targeted other parts of the peplomer. Important. In particular, vaccine-induced antibodies targeted a wider range of locations on RBD than those induced by natural infections, “said NIH.

“These findings suggest that innate immunity against SARS-CoV-2 and vaccine-producing immunity differ in the way they recognize new viral variants. In addition, antibodies obtained with the help of vaccines , Even if the mutant has a new mutation in RBD, it is likely to strongly target the new SARS-CoV-2 mutant, “NIH said.

Reinfection is more common among people over the age of 65.

Reinfection is rare, but more common in the elderly. Danish research Released in March 2021.

In this study, we examined 4 million Danes infected with the virus and calculated the reinfection rate. Studies have shown that older people have about 47% protection against recurrent infections compared to younger people who appear to be about 80% protected from reinfection.

and, Learn at a nursing home in Kentucky It has been found that reinfection in the elderly tends to be more severe than the first attack of the disease.

That was his experience, said Dr. Michael Zaroukian, a family doctor in the Lansing region who specializes in immunology.

“When people get sick again, we see them not only in the office, but in the hospital,” he said.

The strength of innate immunity varies from person to person.

Pre-exposure to SARS-CoV-2 does not guarantee high levels of antibody, nor does it guarantee a strong antibody response to the first vaccination, according to the report. New research From Northwestern University in Chicago.

The study found that people with mild or asymptomatic cases of COVID-19 had lower antibody responses than those with more severe symptoms.

“Many people, and many doctors, assume that previous exposure to SARS-CoV-2 immunizes against reinfection. Based on this logic, among those who have been previously exposed. Some people think that they do not need to be vaccinated, or if they are vaccinated, they only need the first dose of the two-dose Physer / Modelna vaccine, “said the study. Thomas McCaid, a biological anthropologist who was part of the team, said: Press release With the presentation of the research.

“Our study shows that prior exposure to SARS-CoV-2 does not guarantee high levels of antibody, nor does it guarantee a strong antibody response to the first vaccination. Mild or absent. For people with symptomatic infections, the antibody response to vaccination is essentially the same as for people who have never been exposed before. “

Vaccination provides additional protection for people with innate immunity

Unvaccinated people who were previously infected with SARS-CoV-2 were more than twice as likely to be re-infected as those who were previously infected. Recent research From Kentucky.

Similar results were reported in an Israeli study. An Israeli study compared unvaccinated individuals with previously infected individuals who received the vaccine. “In the latter group, the risk of reinfection was significantly reduced,” the study said.

Colorado fitness coach Bill Phillips has frankly supported post-infection vaccination after spending two months in the hospital during his second match at COVID-19.

Phillips, 56, decided not to get vaccinated because she was in the best condition and had antibodies that showed her previous infection. However, he was infected with COVID-19 again in June, infected with a ventilator, and almost died. He has recently been discharged and is in a wheelchair and oxygenated during rehab.

“It didn’t help to be able to do a £ 300 bench press or run a mile straight up the hill,” Phillips said. KUSA-Denver TV.. “I made a mistake. That mistake came very close to sacrificing my life.”

Doctors warn against intentionally trying to acquire innate immunity

Innate immunity can at least provide protection against SARS-CoV-2 reinfection, but doctors say it is a very bad idea for people to be intentionally exposed to the virus.

“It’s like Russian roulette. I hate rolling dice,” said Mark, medical director of the health departments of Huron, Lapia, Sanilac, Tuscola, Arcona, Iosco, Ogemaw, and Oscoda.・ Dr. Hamed.

Since the onset of the pandemic, nearly 2% of Americans with COVID-19 have died, 7% have been hospitalized, and 10% to 30% have experienced “long COVID”. Brain fog and organ damage that lasts weeks or months after the initial infection.

Dr. Rosemary Libero, a pediatric infectious disease specialist at Spectrum Health in Grand Rapids, said the “Russian roulette” factor also applies to children, but younger people are much less likely to have serious cases of COVID. increase.

“We still don’t know whether innate or vaccinated immunity is better in the long run,” she said. “These investigations are underway and we are always looking for that data, so we cannot fully estimate it.

“But the negative effects of vaccination are very small, and the risk of adverse effects of COVID-19 is probably in the range of 3% to 10% for children, so I think vaccination is a safer method. To immunize the population with the virus, “she said.

Scientists said they didn’t want to send the wrong message to the public after an Israeli study was published showing that innate immunity provides strong protection against delta virus reinfection.

Michel Nussenzweig, an immunologist at Rockefeller University in New York, said: Science magazine.. “Because someone can die.”

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