New research is strengthening the evaluation, that is, immunity to COVID-19 lasts for at least 6-8 months after recovery from the disease.
A study published this week in Science Immunology examined 25 patients who had recovered from the disease. Although antibodies (immune system proteins that attack virus particles) begin to drip in blood samples about 20 days after symptoms appear, memory B cells that produce antibodies continue to rise in the blood for 150 days and remain high until 240 days. This indicates that the subject’s body is ready to fight the virus for about eight months.
At the same time, researchers in the other two studies found that people who made antibodies to the coronavirus are much less likely to test positive again within six months or even longer.
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The results of the vaccine heralded good results. The vaccine stimulated the immune system to produce antibodies.
A study published in the New England Journal of Medicine on Wednesday involved more than 12,500 health workers at Oxford University Hospital in the United Kingdom. Of the 1,265 patients who initially had coronavirus antibodies, only two tested positive for active infection in the following six months, and none of them showed symptoms.
This is in stark contrast to the 11,364 workers who initially had no antibodies. In the next six months, 223 of them tested positive for the infection.
The third study by the National Cancer Institute involved more than 3 million people who were tested for antibodies in two private laboratories in the United States. Only 0.3% of people who initially had antibodies later tested positive for coronavirus, while only 3% of people who lacked antibodies later tested positive.
The results show that people with naturally-infected antibodies have a “much lower risk… the same protection you get from an effective vaccine,” said Dr. Ned Sharpless, the director of the virus. . National Cancer Institute.
He said: “Re-infection is very rare.”
The institute’s research has nothing to do with cancer-many federal researchers have turned to coronavirus work due to the pandemic.
Sharpless said it was “good” to see that researchers at the University of Oxford saw the same risk reduction-if antibodies are present, the chance of a second infection is 10 times lower.
The report of his institute is published on a website used by scientists to share research results, and is being reviewed by major medical journals.
This finding is “not surprising… but it is reassuring because it tells people that immunity to the virus is universal,” said Joshua Wolfe, an infectious disease expert at St. Jude Children’s Research Hospital in Memphis. , He had no effect in both studies.
Wolf added: “We don’t know how long this immunity will last.” People have been infected with COVID-19 multiple times, so “people still need to protect themselves and others by preventing re-infection.”