COVID-19 Boosters: Hope or Hype?

Infectious disease expert and NIH-funded researcher Rodger MacArthur, MD, has questions about the evidence on which the Pfizer booster shot recommendations are based.

Making sense out of the recently released CDC recommendations for getting a 3rd shot of the Pfizer COVID-19 vaccine is challenging. Many of the data on which both the FDA and CDC advisory panels based their recommendations have not been published or widely disseminated. In addition, the recommendations are broken down by groups that “should” and “may” get the booster. A close look at the groups reveals substantial amounts of arbitrariness.

For instance, in the “should” get the booster group are those 65 years old or older. Why not 64? Why not 60? In another “should” group are those 50- to 64-year-olds with “underlying medical conditions,” not further specified.

Going to the CDC website helps a bit, but looking at persons with asthma, for instance, the CDC recommends a booster only for those with moderate-to-severe asthma. Unfortunately, there is no definition of moderate-to-severe. Rather, the recommendation is to “check with your doctor.”

Lost in all of the recommendations are a few facts worth considering:

1) Two doses of the Pfizer vaccine are remarkably effective at preventing severe COVID-19 disease and death;

2) Younger individuals who have received 2 doses of the Pfizer vaccine typically have a mild “head cold” if they experience a breakthrough infection;

3) 18- to 30-year-old individuals, especially males, do seem to be at increased risk for post-second dose myocarditis and pericarditis.

Many of the advisors to the FDA and CDC pointed out that there were insufficient safety data in this last age group specific to the risk for these inflammatory heart conditions following a third dose. At the Augusta University Health Center where I work, we have had 2 patients admitted (aged 18 and 22) with myocarditis/pericarditis following their second dose of the Pfizer vaccine. We have had no fully-vaccinated patients in the 18- to 30-year-old age range admitted due to COVID-19.

The Conway Daily Sun (North Conway, NH) recently published data from the New Hampshire Department of Health and Human Services detailing 24 deaths in fully vaccinated persons due to COVID-19 (out of 413 COVID-19-related deaths in NH from January 20, 2021, through September 15, 2021).1 The paper reported that all the deaths were in persons aged 60 years or older, of whom 19 were long-term care facility residents. No further information was given. Consequently, it is not possible from this small data set to determine if being age 60 years and older is an independent risk factor for death due to COVID-19 in the fully vaccinated.

For fully vaccinated persons younger than age 30 years, especially for those with no comorbid conditions (including obesity), I believe it is reasonable to ask, “is getting exposed to SARS-CoV-2 bad?” In other words, and assuming no spread to others, will developing “natural” immunity to the Delta variant provide additional benefit on top of the protection from severe disease provided by the vaccine? I could find no relevant data in the literature that attempted to address this question. I did find a peer-reviewed article that concluded that vaccine-induced immunity gave better protection against variants with single point mutations (ie, new variants) than did natural immunity, say, to the original or alpha variants.2

In general, I support the CDC recommendations concerning boosters. However, I have to side with the CDC advisors who voted against recommending a booster to all health care workers with direct patient contact. All health care workers wear masks when taking care of patients with COVID-19. In my opinion, we need to prioritize increasing the number of health care workers getting their first 2 doses of either the Pfizer or Moderna vaccines, rather than obsessing about boosters. 


  1. West N. 24 fully vaccinated people in NH die from COVID-19. THe Conway Daily Sun. Sept 22, 2021Accessed Sept 27, 2021.
  2. Greany AJ, Loes AN, Gentles LE, et al. Antibodies elicited by mRNA-1273 vaccination bind more broadly to the receptor binding domain than do those from SARS-CoV-2 infection. Sci Transl Med. 2021;13:30 June.

Rodger D. MacArthur, MD, is Professor of Medicine, Division of Infectious Diseases and Office of Academic Affairs, Medical College of Georgia at Augusta University, Augusta, Georgia. Dr MacArthur is an NIH-funded researcher and before arriving at the Medical College of Georgia, he headed the Wayne State University AIDS clinical trial program. He is widely recognized as an authority the development of antiretroviral treatment.