Fact check: Can a cold, flu or flu vaccine cause a positive COVID-19 test?

With the onset of the novel coronavirus, a lot of false claims, doubts and rumours have been circulating in and around the world. Considering the deadly effects of the virus, people have taken extra precautions and measures to protect themselves from the virus. However, they're still grappling with the confusion caused by the combined effects of a cold, flu and COVID-19.

In light of the current pandemic, COVID testing has become one of the most important steps in detecting the virus in people. However, recently, many people have refrained from taking the test, claiming that while they're suffering from a cold or a flu or if they've taken a flu shot, they will definitely test positive for the virus. Many have taken to the social media to render the ineffectiveness and inaccuracy of the coronavirus tests, saying that they're not to be trusted at all.

When it comes to associating common cold with a positive COVID-19 test, it all comes down to the antibody tests. These tests take samples of the blood and detect the disease-specific proteins produced by white blood cells to fight a virus and find out if a person has had a past infection. However, they should not be confused with a diagnostic test.

As per the reports of the Centers for Disease Control and Prevention (CDC), "a positive test result shows you may have antibodies from an infection with the virus that causes COVID-19. However, there is a chance that a positive result means you have antibodies from an infection with a different virus from the same family of viruses (called coronaviruses)."

In terms of the flu, the viruses that define it and the ones that determine the coronavirus are very different and distinct. The flu is caused by an influenza virus, not a coronavirus. Therefore, having contracted a flu or being vaccinated for it will not produce a positive result for COVID-19. According to a spokesperson at the the Food and Drug Administration (FDA), all the tests authorized by them for the coronavirus are specifically checked for cross-reactivity with influenza virus. But none of them have observed cross-reactivity with any of the tests.

As per recent study, the claim that that the common cold, flu and flu vaccine will all result in positive tests for the novel coronavirus is absolutely untrue. COVID-19 tests target a specific and distinct form of genetic material or proteins. Therefore, it is unlikely that other infections, diseases or vaccines will influence the coronavirus test in anyway. It's possible that the common cold will produce a positive result in an antibody test, but those aren't used to diagnose COVID-19.