Thread by @DrEricDing

Don’t do wrong antibody test—many early commercial #COVID19 antibody tests look for antibodies to nucleocapsid, or N, protein. But N antibodies are not as powerful, & not produced by spike protein vaccines (most Western vaccine). @DavidLat’s story.
nytimes.com/2021/06/20/hea…

2) “Most people shouldn’t even be worrying about this,” said Akiko Iwasaki, an immunologist at Yale University.
But antibody tests can be crucial for people with weak immune systems or on certain meds—

3) “encompassing millions w/ organ donations, have certain blood cancers, or who take steroids or other drugs that suppress the immune system. Mounting evidence suggests that a significant proportion of these people do not produce a sufficient antibody response after vaccination.

4) If you must get tested, or just want to, it’s essential to get the right kind of test, Dr. @VirusesImmunity said: “unless they really understood what the test is doing, people might get this wrong sense of not having developed any antibodies.”

5) “If people who were never infected are vaccinated and then are tested for antibodies to the N protein instead of to the spike, they may be in for a rude shock.

6) “@DavidLat , a 46-year-old legal writer based in Manhattan, was hospitalized for Covid-19 for three weeks in March 2020, and he chronicled most of his illness and recovery on Twitter.

7) “Over the following year, Mr. Lat was tested for antibodies numerous times — when he went to his pulmonologist or cardiologist for follow-ups, for example, or to donate plasma. His antibody levels were high in June 2020 but steadily fell over the following months.”

8) “The decline “didn’t worry me,” Mr. Lat recalled recently. “I had been told to expect that they would naturally wane, but I was just happy that I was still positive.”
Mr. Lat was fully vaccinated by March 22 of this year.

9) “But an antibody test on April 21, ordered by his cardiologist, was barely positive. Mr. Lat was stunned: “I would have thought a month after being immunized, I would have antibodies through the roof.”

10) “Mr. Lat turned to Twitter for an explanation. @florian_krammer, an immunologist at the Icahn School of Medicine at Mount Sinai in New York, responded, asking Mr. Lat which test had been used. “That’s when I looked at the fine print on the test,” Mr. Lat said.

11) “He realized it was a test for antibodies to the N protein, not to the spike.

“It seems that by default, they just give you the nucleocapsid one,” Mr. Lat said. “I never thought to ask for a different one.”

12) “In May, the Food and Drug Administration 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.

14) “Many doctors are still unaware of the differences between antibody tests, or the fact that the tests measure just one form of immunity to the virus.”

Read the rest of the story: nytimes.com/2021/06/20/hea…