A negative antibody test doesn’t mean Covishield didn’t work – Quartz India
Man in India fears his Covid-19 vaccine may be vaccinated may not work.
Pratap Chandra, a resident of Lucknow, Uttar Pradesh, was tested for antibodies to Covid 28 days after receiving the Covishield vaccine. After the test concluded that he did not have antibodies against the viral infection, it concluded that the vaccine maker and India’s health ministry were to blame.
Covishield, the AstraZeneca vaccine manufactured by the Serum Institute of India, is the dominant vaccine in the country’s ongoing vaccination program. So far, the majority of the 216 million doses administered in India have been from Covishield.
The course of the law has yet to be determined, but Chandra’s complaint itself may be based on shaky scientific evidence. Antibody tests, experts say, don’t tell you whether a vaccine works or not.
On the one hand, antibody tests can detect if you’ve had an infection in the past due to the type of antibody it tests for. A vaccine, on the other hand, induces a complex variety of antibodies which may not be detectable in a rapid test.
âAfter the vaccines, many [of] people are going to have antibody tests – “Oh, I want to see if that works.” It actually has very little correlation, âsaid Rob Murphy, executive director of the Institute for Global Health and professor of medicine and biomedical engineering at Northwestern University. The Washington Post in February. “A lot of people will test negative on the antibody test, and that doesn’t mean the vaccine didn’t work,” he added.
For this reason, the United States Centers for Disease Control and Prevention (CDC) advises against the use of antibody tests after vaccination, because those who test for specific antibodies – and their correlation between them – can identify a vaccine immune response. These tests, for example, fail to identify a more complex cellular response, which could play a role in vaccine-induced immunity, according to the CDC.
âA vaccinated person should not be alarmed or worried if they receive a negative antibody test result because this test does not detect antibodies from Pfizer, Moderna and Johnson & Johnson’s Janssen COVID-19 vaccines, which have been developed against the virus spike protein, ” says Fernando Martinez, medical director of laboratory medicine at MD Anderson Cancer Center in Texas. Vaccines like Covishield also use the coronavirus spike protein, encoded in the DNA of an adenovirus, to guide cells to create specific antibodies against the disease.