When researchers began to develop what they hoped would be an effective COVID-19 vaccine, they already knew that the H1N1 flu – a new virus, like COVID-19 – affected more severely overweight or obese patients. Patients with a body mass index of 30 or more had a higher risk of hospitalization and death from H1N1.
This is not the first time that such a link has been found. A 2017 study by the University of North Carolina at Chapel Hill found that the flu vaccine was less effective in overweight or obese patients. This study included only 1,022 participants, but other small studies show similar results.
Let’s move on to today, when the COVID-19 vaccine was created, tested on more than 40,000 patients and is now being distributed across the country. The data is promising; the two authorized vaccines offer more than 90% protection against the virus.
But doctors and researchers are aware of the findings of H1N1 and UNC. As a doctor specializing in obesity medicine, I am one of them. Now we all want to know the following: will the COVID-19 vaccines be equally effective in overweight or obese patients? Initial data shows that this is the case, but additional data will need to be collected after many more patients are vaccinated.
What the research says
The answer to this question is crucial. Adult patients with overweight or obesity are among the most affected by COVID-19 and represent more than 70% of the United States population. In fact, when I read the data from the Pfizer vaccine trial, I saw that very familiar group: 70% of the participants in the Pfizer COVID-19 trial, like the demographic group in the United States, were overweight or obese. A collective ovation from obesity experts can be heard around the world for the creation of a group that best represents our current population in the United States.
COVID-19 has been devastating here in the United States for those overweight and obese, particularly younger patients. Initially, doctors thought that younger patients as a whole were less at risk of serious complications due to age. But for people under 50 who are obese, obesity negates the protective effect of age.
The COVID-19 vaccine is promising because it activates the B and T cells of the immune system, essential for long-term protection against viruses. B cell activity and levels have been shown to be lower in both mice and humans with obesity after infections.
These immune cells can produce new antibodies quickly, even if antibody levels drop over time and there are few remnants of previous vaccinations. The antibodies block the virus from entering a cell and infecting it, but B and T cells destroy cells infected by the virus and prevent the virus from replicating and spreading to other cells. But this may not be true for people with obesity. The researchers believe that obesity negatively affects the function of the immune system.
Although patients with obesity can produce adequate antibodies, several studies show that they have a lower level of these B and T cells after an infection with the H1N1 flu. This can alter the typical immune response, leaving the body a step back after the virus has invaded. An important question is whether this altered immune response is also present after a COVID-19 infection. Therefore, we want to know if the vaccine will be as effective in patients with obesity over time as other patients who do not suffer from this disease.
Vaccine is still mandatory
Even with this concern, overweight or obese patients should still receive the COVID-19 vaccine. Even for those obese patients who receive the flu vaccine but still get the flu, there is a reduction of almost 40% in hospitalizations and 82% in ICU admissions.
In short, the data released by Pfizer and the FDA show that the vaccine is not only effective for participants as a whole, but particularly for patients with obesity.
It is encouraging that Pfizer wanted to show that the vaccine was so effective for those who are overweight or obese. Researchers are recognizing that these patients are most at risk and are now preparing studies to reflect this.
Behaviors that will help
Two things can encourage overweight or obese people to exercise and improve their eating habits: previous studies show a positive association between regular exercise before receiving the vaccine and its response to the vaccine, producing up to four times more antibodies after being exposed to a virus or bacteria. This means that antibodies are higher in those who exercised before the vaccine was administered than in those who did not exercise. In addition, it appears that the type and quantity of intestinal bacteria may affect the response to the vaccine. Foods that contain prebiotics and probiotics can help prevent and treat this and other diseases. Prebiotics can be found in barley and garlic, while yogurt, sauerkraut and some cheeses contain probiotics.
More data is needed before we know precisely how overweight and obese patients respond to vaccines when compared to the rest of the population. But that data is coming quickly. Even a year from now, we will look back and be surprised by everything we learn about COVID-19. From this research will come the knowledge that we need to create a better way of providing health care to all of us.
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This article was republished from The Conversation, a non-profit news site dedicated to sharing ideas from academic experts. It was written by: Cate Varney, University of Virginia.
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Cate Varney does not work for, consult, own shares or receive funding from any company or organization that would benefit from this article and has not disclosed relevant affiliations other than his academic appointment.