News

I’m fully vaccinated but feel sick – should I get tested for COVID-19?

Arif R. Sarwari
By Arif R. Sarwari
July 25, 2021

Imagine last night you developed a little runny nose and a sore throat. When you woke up this morning you started coughing and had a fever. In the past year, your mind would have immediately jumped to COVID-19. But if you are already fully vaccinated, you might wonder: Should I still get tested for COVID-19?

Vacciinated1-445x250.jpg
Some people can still get sick after getting vaccinated for COVID-19.

As an infectious disease physician, I am often asked this question. The answer is yes. If you have symptoms of COVID-19, you should get tested for COVID-19 even if you are fully vaccinated. You won’t be at high risk for hospitalization or severe disease, but if you are infected you may pass the virus to an unvaccinated person, who could then get very sick.

Vaccines work but aren’t 100% effective

Researchers have developed some amazing COVID-19 vaccines over the past year. The high efficacy of these vaccines in the closely controlled environment of clinical trials matches their effectiveness in real life. The mRNA vaccines made by Pfizer and Moderna remain over 90% effective in preventing hospitalization or death.

That does not, however, mean that you have the same degree of protection from getting infected.

Vaccinated2-445x297.jpg
Vaccination prevents more than 90% of severe COVID-19 cases, but researchers think that only 70%-85% of vaccinated people are completely protected from any infection.

The latest research estimates that the mRNA vaccines offer 70% to 85% protection from getting infected at all. It’s impossible to know whether a person is fully protected or could still develop a mild case if exposed to the coronavirus.

If you did happen to get infected, you could still spread the virus. And that’s why testing is still important.

What is a breakthrough case?

When a person gets infected with the coronavirus after being fully vaccinated, this is called a breakthrough case. Breakthrough cases demonstrate a basic principle of infectious disease – whether or not a person gets infected depends on the balance between two factors: intensity of exposure and immune competence.

Intensity of exposure relates to how close an uninfected person is to a highly infectious individual spewing virus while talking and how long the two people are in contact. Immune competence relates to the body’s inherent protection against COVID-19. Unvaccinated individuals who’ve never been infected with the coronavirus have no protection – this is a completely new virus after all – while fully vaccinated people will be much more protected.

According to the CDC, as of April 30, 2021, there had been a total of 10,262 known SARS-CoV-2 vaccine breakthrough infections in U.S. states and territories. These are usually asymptomatic or only mildly symptomatic cases, and most don’t result in hospitalization. Breakthrough cases will continue to occur, and though these people are less likely to spread the coronavirus to others than are unvaccinated individuals, they still probably can.

Vaccinated3-890x593.jpg
If you have symptoms of COVID-19, you should still get tested, even if you’ve already been vaccinated.

And what about the SARS-CoV-2 variants? Well, the world has been fortunate that the mRNA vaccines in particular afford significant protection against all major variants that have emerged so far. But it is entirely possible that at some point a coronavirus strain could mutate and partially or fully escape the protection from vaccines. This is yet another good reason to get tested if you are feeling sick.

As vaccination rates rise and daily case counts fall in the U.S. and other countries, it is also important to keep a close eye on the coronavirus. COVID-19 testing allows officials to keep track of how much virus is in a community, and positive test results can help people quarantine before unknowingly spreading the virus to others. So, yes, please get tested if you have concerning symptoms, even if you are fully vaccinated.The Conversation

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Arif R. Sarwari
Arif R. Sarwari

Arif R. Sarwari is a Physician, Associate Professor of Infectious Diseases and Chair of Department of Medicine at West Virginia University

Join the ASBMB Today mailing list

Sign up to get updates on articles, interviews and events.

Latest in Opinions

Opinions highlights or most popular articles

Personal chemistry: Proteomics tackles privacy concerns
Feature

Personal chemistry: Proteomics tackles privacy concerns

Sept. 9, 2021

Sharing raw data is an important norm for the proteomics community. But as clinical studies become more detailed, researchers may need to clamp down to protect patient privacy.

In one week, twice the thanks
President's Message

In one week, twice the thanks

Sept. 2, 2021

This month, during the week of Sept. 20–24, we celebrate both National Postdoc Appreciation Week and Peer Review Week.

Female scientists set back by the pandemic may never make up lost time
Diversity

Female scientists set back by the pandemic may never make up lost time

Aug. 28, 2021

Top researchers get more credit and funding than lesser-known scientists, creating inequality and amplifying gender disparities that hold back women.

Getting the shots
Science Communication

Getting the shots

Aug. 25, 2021

Why do people resist the vaccine? A Lyft driver teaches a scientist an important lesson.

Science denial: Why it happens and 5 things you can do about it
Science Communication

Science denial: Why it happens and 5 things you can do about it

Aug. 21, 2021

It is more important than ever to understand why some people deny, doubt or resist scientific explanations – and how these barriers can be overcome.

Faculty hiring challenges and resilience in the face of a pandemic
Jobs

Faculty hiring challenges and resilience in the face of a pandemic

Aug. 19, 2021

Five members of the board of directors of the Association of Medical and Graduate Departments of Biochemistry talk about difficulties of hiring faculty during the pandemic and lessons learned from the disruption.