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Xinhua News Agency, Geneva, April 25 (Reporter Shen Zhonghao) The report of the World Health Organization’s daily outbreak on the 25th said there is no evidence to date that those who have recovered with the new antibody can protect themselves of “secondary infections”.
The WHO notes that immunity to pathogens through natural infections is a multi-step process that generally takes 1 to 2 weeks. When infected with a virus, the body first develops a non-specific innate immune response. Macrophages, neutrophils, and dendritic cells can slow down the virus infection process and even prevent symptoms from appearing. Following this, the body has an adaptive immune response, producing antibodies that specifically bind to the virus, namely immunoglobulins; it also produces T cells that recognize and kill infected cells, that is, cellular immunity.
The WHO said that if the adaptive immune response is strong enough, it can prevent the disease from becoming a serious condition or prevent “secondary infection” of the same virus. Most of the studies to date have shown that people with new crowns have antibodies to the new coronavirus, but some of them have very low levels of antibodies in their blood. From this it is inferred that cellular immunity can also be crucial for the rehabilitation of patients.
The WHO emphasized that as of April 24, there is no research to assess whether the new coronavirus antibody confers human immunity to the virus. In addition, laboratory tests to detect new antibodies against the coronavirus in humans require additional verification to determine the precision and reliability of the tests.
For some countries, the government suggested that antibody tests be used as the basis for issuing “immunization passports” or “risk-free certificates,” allowing permit holders to travel or resume work. The WHO believes that there is insufficient evidence to demonstrate the effectiveness of antibody-mediated immunity, which in turn cannot guarantee the accuracy of such certificates.
The WHO warns that people whose tests show they have antibodies may think they are free of “secondary infections” and ignore public health recommendations. Therefore, the use of such certificates can increase the risk that the virus will continue to spread.
