In summary

In addition to strengthening the approval process of a COVID-19 vaccine, we should talk about how side effects can signal the vaccine is working.

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By Jessica Saleska

Jessica Saleska is a postdoctoral fellow at the University of California Los Angeles Semel Institute for Neuroscience and Human Behavior,

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Kristen Choi, Special to CalMatters

Kristen Choi is a child/adolescent psychiatric nurse and assistant professor at the UCLA School of Nursing and UCLA Fielding School of Public Health,

Americans are experiencing a crisis-of-confidence over the COVID-19 vaccine: a recent poll by the Pew Research Center found that only 51% of Americans would be willing to get a COVID-19 vaccine if one were available today, down from 72% in May. 

Some of the biggest reasons for this unwillingness are concerns that the vaccine trials are moving too fast without fully establishing safety and effectiveness (78% of poll respondents) and concern about side effects (76% of poll respondents).

Worry over the speed of vaccine development and approval may not be unfounded. The U.S. Food and Drug Administration will consider potential COVID-19 vaccine candidates for emergency use authorization, a temporary approval which takes less time and requires less evidence on safety and effectiveness than a full approval. This authorization, while often used to green-light life-saving medical treatments in times of crises, is virtually unheard-of for the approval of vaccines. 

The unprecedented speed of federal vaccine approval has led to an equally unprecedented local response: on Oct. 19, Gov. Gavin Newsom instituted California’s Scientific Safety Review Workgroup, a panel of scientists tasked to verify the safety of the vaccine after FDA approval of it for distribution. Washington, Oregon and Nevada joined the workgroup soon after, with local leaders heralding the public health benefits of independent expert review. It remains to be seen whether such efforts by state governments will be enough to shift public confidence in the COVID-19 vaccine. 

Beyond concerns over the timeline of approval, potential side effects remain a salient concern for many people, and reporting from early clinical trials of the most promising vaccine candidates show very high rates of side effects, including fatigue (75%), headache (67%), chills (33%), muscle pain (25%), fever (17%), and joint pain (17%). There have been anecdotal reports of more alarming side effects, such as fevers as high as 104 degrees. 

Unlike concerns over the FDA approval process, we don’t need to fear this particular aspect of the vaccine. Counterintuitively, vaccine side effects are actually a reason for optimism.

Vaccines work by taking advantage of the body’s built-in immune response system. They protect us from infection, usually by introducing an inactivated disease agent that does not cause disease, but still signals our body to create antibodies to a specific germ. Vaccine side effects like fever, chills, fatigue and muscle pain are a sign of reactogenicity – that is, a physical manifestation of successful immune response to the vaccine and a signal that the vaccine is working as intended.

Unfortunately for the COVID-19 vaccine, normal signs of reactogenicity also happen to look much like the symptoms of COVID-19. After months of routine temperature checks and self-examinations for fever, chills, muscle aches and other symptoms of COVID-19, it would be easy to erroneously conflate reactogenicity with COVID-19. One could easily conclude that the vaccine causes rather than prevents COVID-19. 

Many Americans already erroneously believe that vaccines cause disease, and such side effects could serve to reinforce this belief. The research is still evolving as to the best strategy to effectively debunk vaccine myths. It is vitally important, then, that the scientific community apply the same rigor to find ways to promote confidence in the COVID-19 vaccine as it does to develop it, especially amid the threat of frequent, COVID-like side effects.  

We can be concerned about the hastened approval process of the COVID-19 vaccine – but we don’t need to be concerned by signals that the vaccine is effective. Side effects indicating reactogenicity may be unpleasant, but they are also transient and manageable. 

The risks that COVID-19 poses on one’s health are far greater than those of the vaccine. In addition to strengthening the approval process of a COVID-19 vaccine, we should start talking about reactogenicity now and seek ways to prevent its reinforcement of false beliefs.  The American public needs more reasons to feel confident about getting the vaccine.

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