Sensational, Misleading COVID-19 Vaccine Reporting

This is a classic headline versus study problem. Except the problem goes beyond the headline. It starts with a preprint of a study. The study has not yet gone through peer review. It goes deep into the weeds of the immune response to Pfizer’s COVID-19 vaccine. But the Guardian doesn’t want to lose its readers in the weeds. So it found a really sensational angle for reporting on this COVID-19 vaccine research. Hence, the false and misleading headline:

Pfizer vaccine may be less effective in people with obesity, says study

There’s just one tiny problem. This was not a study of vaccine efficacy. It was a study of antibody titres. This might be interesting stuff for immunologists. But it tells us absolutely nothing about the effectiveness of this vaccine for preventing COVID-19.

We already know that this vaccine is 95 percent effective for preventing COVID-19. It is just as effective in people with obesity as in people with no risk factors for severe COVID-19.

Gold Standard Evidence

The evidence of excellent efficacy for the Pfizer COVID-19 vaccine is strong because it comes from a large RCT. A total of 34,911 people received either the vaccine or a placebo. The assignment was completely random. Among those subjects were 12,103 people living with obesity.

As you can seen in this table from the FDA review of the Pfizer vaccine, its efficacy is 95 percent in people with obesity. It is 95 percent in people with no risk factors.

Of course, this is a short-term study of effectiveness. We don’t know if the immunity fades over time. We don’t know this for people with obesity. Nor do we know it for anyone else.

What we do know is that this vaccine works quite well within 7 days after a person has had both shots of it. In fact, all three vaccines now approved for use in the U.S. work quite well for people with obesity.

Into the Weeds

The study that prompted this sensational reporting is interesting enough. But it tells us nothing about the clinical effectiveness of this vaccine. They found a different pattern in the humoral immune response to the Pfizer vaccine in people with obesity. It’s an interesting finding. Figuring out what it means will take more research. It does not show that the vaccine is less effective in people with obesity.

As the authors of this paper note, “almost 100% of participants demonstrated antigen-specific
humoral response respect to baseline level.” Further, they note that the role of neutralizing antibodies in SARS-CoV-2 infections is still under investigation. We have much to learn.

In fact, a new peer-reviewed study in Science tells us that immune memory for this virus involves much more than just antibody titres. The authors write:

“Simple serological tests for SARS-CoV-2 antibodies do not reflect the richness and durability of immune memory to SARS-CoV-2. This work expands our understanding of immune memory in humans. These results have implications for protective immunity against SARS-CoV-2 and recurrent COVID-19.”

Vaccine Misinformation

This unfortunate COVID-19 vaccine reporting from the Guardian adds up to misinformation. The study was about humoral immune response. But the headline claimed it was about vaccine effectiveness. This is a false and misleading report we do not need. It can only add to the problem of vaccine hesitancy.

Click here for the detailed data on the Pfizer vaccine posted on the FDA website. For the pre-print study of humoral immune response to the Pfizer vaccine, click here. You can find the peer-reviewed study of immune memory for SARS-CoV-2 here. And finally, you can find further perspective in this commentary published by Obesity.

Novel Coronavirus SARS-CoV-2, transmission electron micrograph by NIAID / flickr

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March 1, 2021