Is ‘Natural Immunity’ From Covid Better Than a Vaccine?

On the heels of last month’s news of stunning results from Pfizer’s and Moderna’s experimental Covid-19 vaccines, Senator Rand Paul tweeted a provocative comparison.

The new vaccines were 90 percent and 94.5 percent effective, Mr. Paul, Republican of Kentucky, said. But “naturally acquired” Covid-19 was even better, at 99.9982 percent effective, he claimed.

Mr. Paul is one of many people who, weary of lockdowns and economic losses, have extolled the benefits of contracting the coronavirus. The senator was diagnosed with the disease this year and has argued that surviving a bout of Covid-19 confers greater protection, and poses fewer risks, than getting vaccinated.

The trouble with that logic is that it’s difficult to predict who will survive an infection unscathed, said Jennifer Gommerman, an immunologist at the University of Toronto. Given all of the unknowns — like a region’s hospital capacity, or the strength of a person’s immune response — choosing the disease over the vaccine is “a very bad decision,” she said.

The primary advantage of a vaccine is that it’s predictable and safe, she said. “It’s been optimally tailored to generate an effective immune response.”

But what do we know about how the immunity from a