Antibody tests and vaccines
Islam News – Some of our readers have recently shared stories about getting antibody tests after receiving their coronavirus vaccines, only to be devastated when the tests came back negative.
In fact, experts say most people don’t need a test to confirm their vaccine’s efficacy. The test results can be misleading or useless.
Extensive clinical trials have already shown that vaccines authorized in the United States trigger a strong antibody response for just about everyone. The exceptions are people with weakened immune systems or those who take certain medications.
To get a reliable answer from testing, vaccinated people would have to get a specific kind of test at the right time. Take the test too soon, or rely on one that looks for the wrong antibodies — all too easy to do, given the befuddling array of tests now available — and you may believe yourself to still be vulnerable when you are not.
Many tests look for a type of antibody that vaccines don’t produce. Many tests seek out antibodies to a protein called the nucleocapsid, or just “N,” which are often plentiful right after an infection. But U.S.-authorized vaccines create antibodies for a different protein, called the spike.
Timing is everything. If you got a vaccine made by Pfizer-BioNTech or Moderna, you need to wait at least two weeks after your second dose. If you got the Johnson & Johnson vaccine, you may need to wait as long as four weeks.
Antibodies are just one aspect of immunity. The body also maintains so-called cellular immunity, a complex network of defenders that also responds to invaders.
The advice is still evolving, in part because the F.D.A. has been slow to wade in.
In May, the agency recommended against the use of antibody tests for assessing immunity — a decision that has drawn criticism from some scientists — and provided only bare-bones information about testing to health care providers. As a result, many doctors are still unaware of the differences between antibody tests.
Source: The New York Times