By Dr. Vivek Sinha

It was approximately one year ago that the world was looking for a tool to protect people from COVID-19. Thanks to the tireless work of thousands of scientists and experts, the world was given not one, but multiple effective vaccines for COVID-19.

Prior to the vaccine rollout, there were tens of thousands of people enrolled in clinical trials to ensure the vaccines were safe. Since the vaccine rollout, hundreds of millions more Americans have been vaccinated successfully showing that the vaccine is not only safe, but it is also effective. While no vaccine can be 100% effective in 100% of the people 100% of the time, the current COVID-19 vaccines offer excellent protection and help fully vaccinated individuals decrease the risk of dying from COVID-19.

Now that we are almost 12 months from the initial Emergency Use Authorization for a COVID-19 vaccine, the questions of waning immunity and the benefits of booster vaccines are being discussed.

At the time of this article being written, the Centers for Disease Control and Prevention has given the recommendation that certain individuals who have previously completed the two-vaccine regimen with either the Pfizer-BioNTech COVID-19 vaccine or the Moderna COVID-19 vaccine more than six months ago are eligible for a booster dose. Specifically, this applies to people 65 years of age and older, and anyone over the age of 18 who either lives in a longterm care setting, has any underlying medical conditions or works in a high-risk setting.

The CDC also advised that adults over 18 who have previously received the Johnson & Johnson COVID-19 vaccine more than two months ago can receive a booster dose.

After much study, the CDC further advised that people who receive a booster dose may “mix and match” the brand of vaccine. This has been deemed safe and effective and it will also give more people access to more doses.

One question that I often field is, “Why do we need booster vaccines in the first place?” In order to answer this very important question, we must know the science behind how vaccines work in the first place.

When we are exposed to a disease – for this example, let’s use polio – the body’s immune system kicks into gear. The body’s defenses look at the disease and quickly build up soldier cells that fight off the infection. Once the infection is defeated, the body keeps a few of those specific soldier cells in case the infection comes back. These soldier cells that remain behind are now considered a part of the person’s immunity against polio.

The problem with building immunity for polio by getting the actual disease is that polio maims or kills many of the people it infects. So even if the person did not die from polio, they could be left severely paralyzed.

This is where vaccines come into play. The purpose of vaccines is to stimulate the body’s immune system without exposing them to the actual disease. Often the immune response in this method of building immunity is more predictable and more robust, thereby giving stronger immunity to the individual.

For many disease processes we know that often multiple doses must be given in order to build up adequate immunity in the individual. One common example is the tetanus vaccine, which is given multiple times in childhood. Multiple doses are needed to provide complete immunity. Once complete immunity has been achieved, we know that it, unfortunately, does not last forever. This is where booster doses come into play.

Boosters are often given months to years after the initial vaccine series. As we have come to learn more about COVID-19 and how our immune system reacts to both the disease process and the vaccines, we are learning that booster doses help increase our immune response and strengthen our protection against the disease as well as decrease our chance of getting very sick if we do catch the virus.

The CDC is the guiding body that the medical community follows in giving vaccines. A unified approach is important when dealing with such a large public health issue. The information coming out can often be daunting and difficult to interpret, so talk to your doctor. He or she will discuss your personal situation and help you decide what you can do to keep yourself healthy this winter season.

Stay informed. Get vaccinated. Stay safe.

The writer is the chief medical officer of Belleview Medical Partners, an office and house call practice based in Old Town.