Home Health Glenn Ellis Ellis: Community, herd immunity and COVID-19

Ellis: Community, herd immunity and COVID-19

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By Glenn Ellis

Even though the speed of the COIVD -19 vaccination campaign has improved somewhat, there are still millions and millions more doses yet to be administered if we are to ever get past COVID-19.

According to The Centers for Disease Control and Prevention (CDC) only 37.1 million people, out of 328 million in this country, have received at least one dose of a COVID-19 vaccine; including about 13.1 million people who have been fully vaccinated. The 48.9 million doses administered, nationally to date, represent only 11 percent of the total population. As you can see, we’ve got a long way to go to get to herd immunity.

What is this herd immunity, and why is it important? Well, measles is a good example. Measles is a highly contagious infectious, viral disease for which we have very effective vaccines. If 93-95 percent of the population is immune to measles, with the available vaccine, then that will protect the entire population. That’s herd immunity.

The COVID-19 vaccines are designed to offer the same public health protection. That’s why folks are so anxious for as many of us to get the vaccine as possible.

Sure, of course you’re going to get individual protection for yourself with a vaccine; but you have to understand that you are never safe from infection as long as the virus is circulating. Viruses, especially this particular coronavirus, have only two purposes: to survive and to replicate. Nothing else matters. However, there is only one requirement; they must have a host to “conduct” their business. In case you haven’t figured it out yet, we’re the host. All that being said, if they have no host, they don’t live. So now you see why herd immunity is so important to this fight to stop COVID.

Vaccines cause the immune system to develop little soldiers (antibodies) that will be on guard, prepared to attack and destroy the COIVD-19 virus if it ever shows its ugly face anywhere inside your body. Without the antibodies, the odds of the virus winning the battle of getting inside your body and infecting you are greatly increased. With the vaccine, those odds are diminished; in the case of Pfizer and Moderna, as much as 95 percent.

Public health experts have estimated that herd immunity would require around 80-90 percent of the population to have COVID-19 immunity, either through prior infection or vaccination. This means that it’s going to take a combination of those of us who have been already infected with COVID-19 (having formed antibodies) and those who receive the vaccine. If the two groups make up 80-90 percent of the population, then the entire population would be protected.

This is because the protection from the antibodies has cut off any opportunity for the virus to find a “host.” No host, no survival or replication for the virus. It truly dies a natural death. There’s no two ways about it, unless, and/or until, the virus tires or “burns” itself out, herd immunity is the only light at the end of the tunnel that’s not a train coming.

Many of us are only stuck on making their decision on getting a vaccine on the confusion around the number of vaccines available. Based on the best estimates from the available data, more than 60 vaccines are still going through a three-stage clinical trial. We already have several currently available, including Pfizer; Moderna; Astra-Zeneca; Johnson & Johnson, among others.  The Pfizer, Moderna and Oxford/AstraZeneca coronavirus vaccines require two shots. After the initial vaccine dose, a second shot is given three to four weeks later. You need both COVID-19 vaccine doses to reach full immunity; the level of protection increases dramatically (from 52 percent to 95 percent) after the second shot. Researchers are also unclear whether the lower level of immunity from just one shot would last long. Bottom line…all vaccines work by exposing the human body to substances that trigger an immune response, creating protection from future infection.

Regardless of which vaccine you get, you won’t get the full protection until two weeks after your second or final dose. That’s about how long it takes your immune system to mount an antibody response to the vaccine.

Oh, a word for those who think getting a vaccination is a ticket to freedom from “COVID-19 jail”. Whether you’re vaccinated or not, your life won’t change right now.  To protect the people around you, it is important to continue the same safety precautions such as mask-wearing and avoiding gatherings for a little while longer. While we know that the vaccines are expected to be great at protecting the person who received them from getting COVID-19, we don’t know how good they are at preventing that person from contracting and passing the virus. The vaccine is a really important tool, but it’s just one of a combination of tools needed to control and end the pandemic.

A final note to those 5-20 percent of you who will benefit from herd immunity because the other 80-95 percent of everyone else gets the vaccination. Obviously, you’re right – you don’t have to get the vaccine to get the protection and benefit of herd immunity; but at least be honest with yourself about the real reason you aren’t getting a vaccine. As always, “information is the best medicine”…

Glenn Ellis, MPH is a Visiting Scholar at The National Bioethics Center at Tuskegee University and a Harvard Medical School Bioethics Fellow. Ellis is an active media contributor on Health Equity and Medical Ethics. For more good health information visit: www.glennellis.com