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This is a weekly Q and A column written by Dr Lydia S. Segal, M.D. in conjunction with Chaffee County Public Health. This column is focused on questions readers have about COVID-19 news and sciences.  As Segal points out, ‘Everything I write today is valid for today. COVID-19 news and science are rapidly evolving, assume updates will be made”

QUESTION:   A reader asks, ‘What do vaccines actually do, protect me from getting infected or from getting sick?”

Lydia S, Segal, MD, MPHANSWER:  Vaccines are designed to protect us from disease but not from infection. Therefore, there will always be a small percentage of the population that will get infected and develop the disease. But when they do get sick, they do not get as sick as those who were never inoculated.  In the case of the vaccines developed to protect us from SARS-CoV-2, the vast majority of people who do end up getting sick, get a milder form of COVID-19.

QUESTION: A reader asks, “I am confused about the breakthrough cases reported in the Chaffee County Dashboard. I thought if you got vaccinated, you couldn’t get COVID-19. What gives?  (Chaffee County Dashboard site:

ANSWER: The mRNA vaccines Pfizer and Moderna, which account for about 96 percent of the vaccines used in the county, were shown in both clinical trials from last year and in bigger population studies in the spring of 2021, to have about a 95 percent efficacy rate. This means that out of every 100 people who are fully vaccinated, 5 will get infected and develop COVID-19. Therefore if 1,000 people get vaccinated we would expect 50 people to develop COVID-19. And if 11,000 people have been fully vaccinated in the county, based on Chaffee County Public Health’s dashboard, then you might expect to see 550 get sick.  Yesterday the dashboard was showing 66 cases.

It is assumed that non-pharmaceutical measures such as masking, social distancing, and hand washing are impacting the level of contagion and therefore illness. So when you combine mitigation measures with a very robust vaccine, more people stay healthy. And of those that do get sick, fewer end up in the hospital if they were fully vaccinated.

QUESTION:  I have gotten several questions about boosters. Should I get a booster? When should I get a booster if I am going to get one? And should we not be sending all spare shots overseas where people, in particular health care workers in third world countries, do not have adequate vaccine supplies?

ANSWER:  These are all great questions. Let me take them one at a time.

As stated in previous Q and A columns, all vaccines lose some of their potency over time. The efficacy of a particular vaccine can often depend on how the vaccine is developed, what variants it is designed to guard against, and how prevalent it is in the community.  But all vaccines over time, be it months to years to decades, lose some of their potency.

It has been found that the mRNA vaccines lose maybe one percent or more of their efficacy per month. This is mostly due to the presence of variants and of those who are not vaccinated serving as a reservoir of viral transmission, giving the virus an opportunity to change.

It is clear that those who are immunocompromised due to medications they are on such as immunosuppressives, or chemotherapy, should strongly consider getting a booster. This is FDA/CDC approved. The booster should be given approximately 8 months after their second mRNA vaccine.

The question of whether the general population should get a booster is still somewhat under debate. It is more a question of when they should get one, rather than if they should. This is best discussed with each individual’s physician.  Some people may decide to wait a few extra months if they are healthy and have no problem following mitigation measures such as masking, social distancing, and hand washing.

Lastly is the ethical question of should we as a country be given a third dose to the general population when there are millions of people in third world countries without adequate supplies, in particular health care workers.

My professional suggestion, and one I offer to close personal friends and family as well, is to look at your own situation, taking into account your age, your health status, and your ability to protect yourself on a daily basis. And discuss your options with your physician.

For more information about COVID and vaccines, eligibility, and appointments, see the links below. Pharmacies are getting small shipments of vaccines. Information will be posted online here and on the county public health and hospital web pages.

Pharmacies with vaccine clinics:

Salida:  Safeway, Walmart, and Salida Pharmacy

Buena Vista: Mt. Shavano (LaGree’s), City Market, BV Drug, and Valley-Wide Health

If you have questions you would like Dr. Segal to address in a future COVID Q and A column, please write to

By Lydia S. Segal, M.D., MPH