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  • Writer's pictureP.K. Peterson

Keeping Our Defenses Up: Update on COVID-19 Vaccines

“As the Omicron threat subsides and we start to look forward to better days ahead, it will remain critical for researchers and policymakers to continually evaluate and revise vaccination strategies and recommendations, to keep our defenses up as this virus continues to evolve.”

- Lawrence Tabak, D.D.S., Ph.D., Acting Director, National Institutes of Health

“Inside of a ring or out, ain’t nothing wrong with going down. It’s staying down that’s wrong." - Muhammed Ali, American professional boxer and activist

SARS-CoV-2 has knocked us down but certainly not out. Last week the U.S. Labor Department’s monthly job report was strong signaling workers returning to the labor market due to the falling number of COVID-19 cases. We’ve arrived at this point through the dogged work of countless people, especially those responsible for developing and rolling out highly effective and safe vaccines in record time. They deserve a standing ovation. Fortunately, the vaccine industry isn’t resting on its laurels and is developing new vaccines to fight this virus. In this Germ Gems post, I provide an update on the status of the COVID-19 vaccine medicine cabinet.

The workhorse vaccines. The U.S. Food and Drug Administration (FDA) has given full approval to two mRNA vaccines—one from Pfizer-BioNTech and one from Moderna/NIAID—and an emergency use authorization (EUA) to Janssen/Johnson & Johnson’s adenovirus-vectored vaccine. These three vaccines, introduced at different times and with different stages of approval for children, are America’s “workhorse vaccines.” As of early March 2022, 81% of Americans five-years-of-age or greater had received at least one vaccine dose, and about three-quarters of those eligible had received a booster inoculation.

The World Health Organization (WHO) has granted EUA to 10 COVID-19 vaccines. (The Pfizer, Moderna, and J&J vaccines are included in this total.) According to the WHO’s “Vaccine Tracker,” about 11 billion COVID-19 vaccinations have been given worldwide, and close to 65% of the world’s population has received at least one vaccine dose. Unfortunately, this includes only about 11% of all people in low-income countries. This global disparity is especially disturbing because in the U.S. millions of doses of COVID-19 vaccine have expired or are about to and will have to be discarded.

Waning of vaccine effectiveness. Because vaccination-induced immunity falls over time, many researchers have studied and are continuing to study the waning of the effectiveness of the COVID-19 vaccines. It is an issue of importance to the public health of the world.

Some studies suggest that immunity to natural COVID-19 infection—so-called “natural immunity”—is more robust than vaccine immunity with little waning for a year following infection. According to the Center for Disease Control and Prevention (CDC), however, natural immunity to COVID-19 infection can decay within about 90 days whereas immunity from COVID-19 vaccines has been shown to last longer. Both the Pfizer and Moderna mRNA vaccines are reported to provide strong protection for at least six months. Studies are ongoing to evaluate the full duration of protective immunity after vaccination with the Janssen/Johnson & Johnson vaccine. (Manufacturing of the Janssen/Johnson & Johnson vaccine has been beset recently with problems and uptake of the vaccine has sputtered.)

In the article “Risk of infection, hospitalization, and death up to 9 months after a second dose of COVID-19 vaccine: a retrospective, total population cohort study in Sweden” in the February 26, 2022 issue of The Lancet, researchers published the results of one of the most comprehensive studies to date for several vaccine regimens, including the Pfizer and Moderna vaccines. (Of note, the study period antedated the emergence of the Omicron variant.) The research showed that although the rate of immunity waning differed according to the vaccine type, vaccine effectiveness against severe COVID-19 seemed better maintained regardless of vaccine type. The results of this study also strengthened the evidence for the need of a third vaccine dose as a booster.

The authors of an accompanying Lancet editorial raised this question “Has the current generation of vaccines reached its maximum potential?” They concluded, “It is urgent that we develop coronavirus vaccines that are more broadly protective with durable protection against both infection and disease.”

Vaccines in the pipelines. The New York Times’ “Coronavirus Vaccine Tracker” reported recently that researchers are currently testing 118 vaccines in clinical trials on humans, and 50 have reached the final stages of testing. This is encouraging news.

In addition, the FDA is evaluating other vaccines including some that have already received WHO EUA approval. In fact, after a series of delays, the American biotechnology company Novavax recently submitted an FDA EUA request for its spike protein-based vaccine NVX-CoV2373 for use in people 18 and older.

The FDA did reject, however, an EUA application for pediatric use of Covaxin, an India-made vaccine on WHO’s EUA list. But another India-made spike protein-based vaccine, Corbevax, is showing promise. (And, it is patent-free.) Finally, on February 24, Sanofi and GlaxoSmithKline announced that they will soon be seeking FDA approval for their modified spike protein vaccine both as a primary vaccine series and a booster.

Who should get a booster and when? With a few medical exceptions, it is now generally advised that everyone who has received one of the three “workhorse” COVID-19 vaccine regimens should get a third dose (referred to as a “booster.”) Additionally, individuals who are immunocompromised and fully vaccinated with three shots should consider getting a fourth booster dose now. For advice about who should receive what COVID-19 booster, the CDC’s website “COVID-19 Vaccine Booster Shots” provides up-to-date information. And if you are immunocompromised (or think you might be), the CDC also provides useful definitions and recommendation regarding getting a fourth shot—see their website “COVID-19 Vaccines for Moderately or Severely Immunocompromised People.”

As immunity wanes in everyone who is vaccinated, you might wonder, “Why shouldn’t everyone get a fourth ‘booster’ dose now?” (Moderna has made the case for a fourth COVID-19 vaccine booster this year.) Or you may ask “Will everyone need an annual COVID-19 vaccine?”, much as is recommended for flu shots for everyone six months of age or older to prevent seasonal influenza?. My answer to both of these questions is: Stay Tuned. Let’s wait for scientific evidence that supports these ideas.

COVID-19 vaccination of children. Because COVID-19 is a milder disease in children than in adults and vaccine safety data in children has accumulated more slowly, recommendations for vaccination in younger people are still evolving. That said, most children and all teens can (and should) get vaccinated. For detailed information, including advice about which vaccines to use as boosters and the rationale behind why vaccination of children is considered critical, see the CDC’s website: “COVID-19 Vaccines for Children and Teens.”

On a related note, substantial evidence supports the importance of vaccinating pregnant women, not only to protect mothers against severe COVID-19 but also to prevent COVID-19 in newborns due to passive immunization that occurs during gestation. (For more information, see maternal-fetal medicine specialist Dr. Jacqueline Parchem’s article, “The Onus Is on Us to Get Our Pregnant Patients Vaccinated,” published in February in MEDPAGETODAY.)

Keeping the pressure to vaccinate on. President Biden recently declared, “We will never give up on vaccinating more Americans.” Nearly 60 million American adults—about one quarter of the population—remain unvaccinated against COVID-19. Many of the unvaccinated are vaccine hesitators or vaccine skeptics, a topic that I’ve addressed in several previous Germ Gems posts, most recently on February 2, 2022, “The Post-Truth Era Has Fueled COVID-19 Vaccine Hesitancy.” As I mentioned in the previous Germ Gems posts, vaccine hesitancy and anti-vax movements are as old as vaccination itself. The only thing that’s really new is the Internet (Social Media)-based profusion of vaccine misinformation.

In her article “The Long, Strange History of Anti-Vaccination Movements” published on March 4, 2022 in Vox, Anna North reviewed the history of vaccine hesitancy. She identified the critical issue in vaccine hesitancy to be lack of trust, especially of government and public health authorities. According to North, “The challenge then, is to convince people to trust the public health system enough that they will accept treatment whose benefits they may not see right away—or ever. History shows such trust is possible, but it has to be earned. And when trust is broken, it may take generations to repair.”

Restoring trust in our public health system is an enormous challenge. But so was the development and distribution of COVID-19 vaccines— a goal accomplished in record time. Now that the reasons underlying vaccine hesitancy are becoming better understood, let’s hope innovative programs that foster trust in our public health system are expedited before the next pandemic emerges.

A stellar example of such innovative thinking is the University of Maryland School of Public Health’s initiative “Shots at the Shop.” Called “From Vaccine Hesitancy to Vaccine Confidence,” their Training Program aims to engage 1000 black-owned barbershops and hair salons nationwide to act as health advocates. Participants assist their clients in making informed COVID-related decisions, dispelling misinformation and hosting COVID-19 vaccination clinics in their shops. Because COVID-19 threatens every community in the world, we need more community-minded programs like this that can cut through government bureaucracy and restore trust in public health.

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Main Page images courtesy of Shuxian Hu, MD. Dr. Hu is a scientist in the Neuroimmunology Research Laboratory at the University of Minnesota.

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