https://blog.wenxuecity.com/myblog/73054/202102/567.html
一盘菜价，求得心安
上海妹子几周前打了JJ，今天去CVS测，不知咋样了
顺便提一下：CDC不建议打过疫苗的去测抗体，认为一旦阴性，不好解释，是在找麻烦。
https://www.cdc.gov/coronavirus/2019-ncov/lab/resources/antibody-tests-guidelines.html
- Antibody testing is not currently recommended to assess for immunity to COVID-19 following COVID-19 vaccination or to assess the need for vaccination in an unvaccinated person. Since vaccines induce antibodies to specific viral protein targets, post-vaccination serologic test results will be negative in persons without history of previous natural infection if the test used does not detect antibodies induced by the vaccine.
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Vaccination
SARS-CoV-2 infection begins when the RBD of the S protein of the virus binds to the angiotensin-converting enzyme 2 (ACE-2) receptor site in humans, the initial step in viral entry into human cells. Preventing SARS-CoV-2 from binding with ACE-2 receptors in the respiratory tract of humans can prevent infection and illness. This interaction between S protein of SARS-CoV-2 and the ACE-2 receptor sites has been the major focus of vaccine development. The vaccine candidates that have received EUA or are in late stage development aim to elicit neutralizing antibodies against the S protein or the RBD (31). Data from two phase III mRNA vaccine efficacy trials demonstrated up to 95% efficacy following a two-dose vaccination series (32, 33). It is unknown whether natural infection confers a similar degree of immunity compared to vaccination.
Natural SARS-CoV-2 infection results in antibody development against viral proteins including the N and S proteins, including the RBD of the S protein. Vaccine induced antibody development has implications for serologic testing. Before vaccine introduction, a SARS-CoV-2 serologic test that detects any of the N, S or RBD antibodies could be considered to indicate previous exposure to SARS-CoV-2. With the introduction of vaccine, vaccinated persons may test positive by serologic tests for the vaccine antigenic target (S and S subunits, including RBD) but not against other non-target proteins. Thus, history of vaccination and/or prior SARS-CoV-2 infection must be considered when interpreting serologic test results. Further, many persons infected with SARS-CoV-2 will be asymptomatic and never tested by viral detection tests, further complicating the interpretation of subsequent serologic testing. Testing for antibodies that indicate natural infection could be a useful public health tool as vaccination programs are implemented, provided the serologic tests are adequately validated to specifically detect antibodies to specific proteins (or antigens). Although an antibody test may employ a specific antigen(s), antibodies developed in response to different proteins may cross-react (i.e., the antigen(s) may detect antibodies it is not intended to detect), and therefore, may not provide sufficient information on the presence of antigen specific antibodies. For currently FDA authorized tests, it has not been established whether the antigen(s) employed by the test specifically detects only antibodies against that antigen and not others. Furthermore, none of the currently authorized tests have been specifically authorized to assess individuals who have received a vaccine. However, the EUA indications for currently authorized tests do not preclude the use of these tests on individuals who have received a SARS-CoV-2 vaccine. Vaccination may cause false-positive results for tests that utilize the S antigen or subunits like RBD, but not for tests that use the N antigen.
