COVID immunity through infection or vaccination - Are they equal?

Dr. Aaron Kheriaty, a University of California-Irvine psychiatry professor, felt he didn’t need to be vaccinated against covid because he’d fallen ill with the disease in July 2020.

So, in August, he sued to stop the university system’s vaccination mandate, saying “natural” immunity had given him and millions of others better protection than any vaccine could.

A judge on Sept. 28 dismissed Kheriaty’s request for an injunction against the university over its mandate, which took effect Sept. 3. While Kheriaty intends to pursue the case further, legal experts doubt that his and similar lawsuits filed around the country will ultimately succeed.

That said, evidence is growing that contracting SARSCoV-2, the virus that causes covid-19, is generally as effective as vaccination at stimulating your immune system to prevent the disease. Yet federal officials have been reluctant to recognize any equivalency, citing the wide variation in covid patients’ immune response to infection.

Like many disputes during the covid pandemic, the uncertain value of a prior infection has prompted legal challenges, marketing offers and political grandstanding, even as scientists quietly work in the background to sort out the facts.

For decades, doctors have used blood tests to determine whether people are protected against infectious diseases. Pregnant mothers are tested for antibodies to rubella to help ensure their fetuses won’t be infected with the rubella virus, which causes devastating birth defects. Hospital workers are screened for measles and chickenpox antibodies to prevent the spread of those diseases. But immunity to covid seems trickier to discern than those diseases.

The Food and Drug Administration has authorized the use of covid antibody tests, which can cost about $70, to detect a past infection. Some tests can distinguish whether the antibodies came from an infection or a vaccine. But neither the FDA nor the Centers for Disease Control and Prevention recommend using the tests to assess whether you’re, in fact, immune to covid. For that, the tests are essentially useless because there’s no agreement on the amount or types of antibodies that would signal protection from the disease.

“We don’t yet have full understanding of what the presence of antibodies tells us about immunity,” said Kelly Wroblewski, director of infectious diseases at the Association of Public Health Laboratories.

By the same token, experts disagree on how much protection an infection delivers.

In the absence of certainty and as vaccination mandates are levied across the country, lawsuits seek to press the issue. Individuals who claim that vaccination mandates violate their civil liberties argue that infection-acquired immunity protects them. In Los Angeles, six police officers have sued the city, claiming they have natural immunity. In August, law professor Todd Zywicki alleged that George Mason University’s vaccine mandate violated his constitutional rights given he has natural immunity. He cited a number of antibody tests and an immunologist’s medical opinion that it was “medically unnecessary” for him to be vaccinated. Zywicki dropped the lawsuit after the university granted him a medical exemption, which it claims was unrelated to the suit.