Should You Get a COVID Shot? Doctors Weigh the Risks and Benefits of mRNA Vaccines

Understanding mRNA Vaccines: Safety, Efficacy, and the Future of Immunization

The recent decision by U.S. Health and Human Services Secretary Robert F. Kennedy, Jr., to cancel nearly $500 million in mRNA vaccine research contracts has sparked a broader conversation about the safety and future of this groundbreaking technology. While the move focuses on respiratory viruses like swine flu, it raises questions about the role of mRNA vaccines in public health.

Currently, the only widely available mRNA vaccines are those developed for COVID-19. These vaccines have been instrumental in reducing severe illness, hospitalizations, and deaths during the pandemic. However, the cancellation of funding for research into other respiratory viruses has led to debates about the effectiveness and risks of mRNA technology.

Kennedy stated that after reviewing scientific data and consulting with experts from the National Institutes of Health (NIH) and the Food and Drug Administration (FDA), the HHS determined that mRNA technology poses more risks than benefits for certain respiratory infections. He emphasized shifting funding toward safer, broader vaccine platforms that remain effective even as viruses mutate.

Despite these claims, many experts have challenged the notion that mRNA vaccines are unsafe or ineffective. Rick Bright, former director of the Biomedical Advanced Research and Development Authority (BARDA), warned that cutting mRNA development now could leave the country unprepared for future health crises. He argued that the rapid development of the first mRNA vaccines during the pandemic demonstrated their potential to save lives and prevent serious illness.

How Do mRNA Vaccines Work?

Vaccines typically work by stimulating the immune system to recognize and fight off pathogens. Traditional vaccines use weakened or dead versions of a virus to trigger an immune response. In contrast, mRNA vaccines do not contain any live virus. Instead, they deliver a piece of genetic code that instructs cells to produce a harmless protein found on the surface of the virus. This protein then triggers the body’s immune system to create antibodies, preparing it to fight off the actual virus if exposed.

This technology was first explored in the 1970s but faced challenges due to the body's natural defenses against foreign RNA. Advances in biotechnology allowed scientists to encapsulate the mRNA in a fatty bubble, enabling it to enter cells and deliver its message effectively.

The Safety and Effectiveness of mRNA Vaccines

Clinical trials and real-world data have shown that the mRNA vaccines for COVID-19 are safe and highly effective at preventing severe illness, hospitalization, and death. According to the Centers for Disease Control and Prevention (CDC), these vaccines underwent the most intensive safety analysis in U.S. history. They also noted that the technology provides a powerful tool for protecting against serious illness.

For adults aged 18 and older, the 2023–2024 vaccines significantly reduced ICU admissions and deaths in the first two months after vaccination. They also decreased emergency department visits and hospitalizations by 50% and lowered the risk of long-term complications associated with the virus.

While protection may wane over time, the vaccines continue to reduce critical illness by approximately 50% and hospitalization risk by 30%, according to the CDC. Dr. Michael Mina, an immunologist and epidemiologist, emphasized that while the current vaccines are safe, future mRNA vaccines must be individually assessed for safety and efficacy.

Side Effects of mRNA Vaccines

Like traditional vaccines, mRNA vaccines can cause common side effects such as soreness at the injection site, fatigue, headache, muscle pain, and fever. Rare side effects, including myocarditis and pericarditis, have been reported in male adolescents and young adults after receiving the Pfizer and Moderna vaccines. However, experts stress that these cases are rare and that the risk of these conditions is higher after a COVID-19 infection than after vaccination.

In May 2024, the FDA required Moderna and Pfizer to add warning labels to their vaccines to include new safety information about the risks of myocarditis and pericarditis. Individuals who experience these conditions after vaccination should consult their doctor to weigh the risks and benefits of additional doses.

Should You Get the mRNA Vaccines?

The only currently available mRNA vaccines are those for COVID-19. A non-mRNA vaccine, developed by Novavax, is also available. Experts like Dr. Aaron Glatt emphasize that mRNA vaccines remain a key tool in protecting against the virus, especially for those at higher risk.

Dr. Mina notes that while the marginal gains from boosters may be smaller, they still provide some level of added protection. For example, a healthy young person might gain around 20% more protection for 60–90 days after a booster. However, the benefits tend to diminish over time.

Are You Eligible for the Latest Vaccine?

The 2024–25 updated COVID-19 vaccine is still available for most adults 18 years and older. It is expected to be available this fall, though eligibility and insurance coverage remain unclear due to changes in CDC guidelines and restrictions on authorizations for healthy adults and children.