Much remains a mystery about COVID-19 antibodies.
How much immunity do the antibodies confer? How long does that immunity last? Should people be tested for antibodies? Does a positive test result mean that someone is immune to the coronavirus?
Here are some of the latest ideas about coronavirus antibodies and immunity and what that means for a vaccine.
Antibodies to the coronavirus appear to confer immunity, but it is unclear how long it lasts.
People with antibodies are very likely to have some protection against reinfection.
“I think they do. I just don’t know for how long, “said Dr. Matthew Sims, an infectious disease specialist at Beaumont Health in the Detroit metropolitan area. Sims is leading a major Beaumont study of COVID-19 antibodies and antibody testing.
“It’s complicated,” said Sims. “Several documents have come out that talk about people who seem to lose antibodies quickly, and that seems more common in asymptomatic cases, where people never knew they were sick. But it also happens in others. “
Dr. Russell Lampen, infectious disease specialist for Spectrum Health in Grand Rapids, offered similar ideas.
“I think the only thing we can say is that: the pandemic started in late 2019, and we have yet to see a credible case of reinfection,” he said. “Therefore, it is assumed that there is probably some protective immunity, but no one knows the duration of the immunity.”
Even if the antibodies cannot be detected, other immune responses may offer protection.
“Not all immunity appears to be related only to antibodies,” said Lampen. “There are a couple of different ways the immune system works, and the other way that our body fights infections is with T cells, and it seems that T cell levels stay elevated for a time after infection.” .
Sims makes the same point.
“Most of the immunity we get is based on the cellular component, rather than the antibody component, although the two work together,” Sims said. “There is some data that even if people lost the antibodies, maybe cellular immunity will take over.”
One reason for such optimism is the dearth of reported cases of coronavirus reinfection.
While there have been a few cases where people tested positive for COVID-19 again after testing negative, Sims said those cases appear to involve dead viruses that are still being killed, and the COVID diagnostic test can detect those dead cells. .
“I think what is happening is that the cells infected with the virus are starting to die, just like normal cells are turning around, and you are detecting viruses still in the cell but not infectious,” said Sims. “Am I 100% sure? Not.”
Dr. Sandro Cinti, an infectious disease specialist at Michigan Medicine at the University of Michigan, is also skeptical of reports of people being reinfected with coronavirus.
“I don’t know if there is still convincing evidence for that,” he said. “What we do know is that people can remove the virus for a long time, and even if you have a dead virus in your nose, it will be recorded in the PCR test.”
“So imagine someone leaving the hospital. They have passed their COVID and have other symptoms, they come back and retest and they are positive, ”she said. “They are probably positive from being positive before, and their new symptoms may not be associated with COVID at all. I’m not sure there is a convincing study showing that reinfections are happening to a great extent. ”
At this point, there is no “immunity pass”.
“I know that people want to know that if they have been infected with COVID, if they have a positive antibody test, they don’t have to wear a mask and they don’t have to worry about infecting their grandchildren and they can go and hug everyone,” Cinti said. “We can’t say that yet.”
“I don’t think just because you have antibodies, you should take it as ‘I can go out there and do whatever I want,'” Sims agreed. “You should take the same precautions as everyone else, because the reality is that you have immunity, but we don’t know for how long or how strong it is.”
Even with questions about antibody protection, antibody tests can provide valuable information.
“The best way to use antibody tests at this time is for epidemiological purposes, that is, what percentage of the population was infected,” Cinti said.
“Another reason to evaluate people is that they are using antibodies from people who were infected to treat other people, it is called convalescent serum,” he added. “By evaluating people, we get a group of people who can donate blood in case this gets worse again.”
When it comes to antibody testing, “there are people who get it who don’t need it, and there are people who should get it and haven’t received it,” Sims said.
“It is definitely worth checking if you think you have had COVID and you are not sure,” he said. “If your doctor recommends testing, it is probably reasonable to do it. And sometimes people just want to know: Do I have antibodies? Was I exposed? And that’s reasonable, given the state of things. “
A positive antibody test “could provide you with a certain degree of comfort in that your risk is likely to be less of reinfection or infection,” Lampen said. “I think that is reassuring. But I can’t tell people that this gives some kind of license or permission to change their behavior. “
3.1% of the antibody tests administered by Spectrum Health have been positive
More than 200,000 antibody tests have been administered in Michigan, although the state has not released the results of those tests.
However, Spectrum Health in Grand Rapids has released its numbers: The health system has conducted 11,245 tests, and 3.1% have tested positive.
Many of them have been health workers, as well as people in the public wondering if they have been exposed to the disease, Lampen said.
There is general optimism about a vaccine.
Even if the antibodies fade rapidly in some people, doctors told MLive that they are optimistic about developing a vaccine that will provide effective protection.
“I don’t think what we’ve seen so far in terms of antibodies discourages me or should lead anyone to believe that we can’t develop a vaccine for this,” Cinti said.
“Some of the new vaccines that seem to elicit or create both a T cell response and an antibody response, and that will be important,” said Lampen.
However, it is unclear how long the vaccine would be effective in individuals.
“COVID can be like a flu shot, where you need it every year,” said Sims. “If it works and you need it every year, it could be combined with the flu shot so that you get a vaccine that protects you from both the flu and COVID. It’s possible.
“I can’t say with 100% certainty that a vaccine will be ready by the end of the year,” said Sims. “I can say that they are working faster and harder and with more money than any other vaccine development project.”
COVID-19 PREVENTION TIPS
In addition to washing their hands regularly and not touching their faces, officials recommend practicing social distancing, assuming anyone can carry the virus.
Health officials say you should stay at least 6 feet away from others and work from home, if possible.
Use sanitizing wipes or sanitizing spray cleaners on frequently touched surfaces in your home (door handles, faucets, countertops) and carry hand sanitizer when you go to places like stores.
Michigan Governor Gretchen Whitmer also issued an executive order requiring people to cover their faces with their mouths and nose inside closed public spaces.
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