Can a person still test positive for COVID-19 following a booster shot? Here's what you need to know
The COVID-19 booster shots have been instrumental in our fight against the pandemic. Here's what you need to know about their effectiveness, side effects, and duration.
The booster shots reduce the risk of contracting SARS-CoV-2 by 55% to 99%, according to various studies. However, it is possible to test positive for COVID-19 after receiving a booster shot, even though the booster shot does not cause an infection. This phenomenon is known as a breakthrough infection.
When a person gets a breakthrough infection, their symptoms are more likely to be mild, and they are significantly less likely to become severely ill. It's important to note that protection against disease declines quickly, but protection against severe infection, hospitalization, and death lasts longer.
Common side effects of the latest COVID-19 mRNA booster vaccines include pain, swelling, or redness at the injection site, fatigue, headache, muscle pain (myalgia), joint pain (arthralgia), chills, nausea or vomiting, fever, and swelling of lymph nodes in the armpit or groin. These side effects are generally mild to moderate and resolve within a few days.
Rare but notable side effects include myocarditis and pericarditis (inflammation of the heart muscle or surrounding lining), predominantly in males aged 12 to 29 years. While rates have decreased with subsequent boosters, the FDA continues to monitor these risks carefully.
Booster doses enhance immunity against COVID-19 variants, including Omicron. Early data showed a 20- to 40-fold reduction in neutralizing activity against Omicron with the original two-dose series, but booster doses restore vaccine effectiveness against symptomatic disease to about 70–75%, with higher effectiveness expected against severe disease. Protection wanes over time, generally lasting months, though precise duration can vary based on variant and individual immune response.
Updated boosters targeting newer variants are designed to extend and broaden protection. The newest COVID-19 booster provides protection against some types of Omicron variants, while the new bivalent booster offers protection against now dominant Omicron variants.
According to the CDC, people should seek a bivalent booster if it has been more than 2 months since their last monovalent booster. People who have recently had COVID-19 may wait up to 3 months after their most recent infection before taking the booster. There are very few medical reasons not to get the COVID-19 vaccine and boosters.
It's important to note that even after having COVID-19, a person can still contract the virus, but a vaccine offers additional protection. It is not known to what extent people with an asymptomatic infection can spread the virus or their specific role in its spread.
In summary, the COVID-19 booster shots provide substantial protection against symptomatic and severe COVID-19, but protection wanes over several months. Common side effects last a few days and include injection site symptoms, fatigue, headache, and muscle pain. Rare cardiac inflammation can occur, mostly resolving with treatment. Ongoing surveillance and updated vaccines aim to maintain optimal protection.
[1] Centers for Disease Control and Prevention. (2022). COVID-19 Vaccines. https://www.cdc.gov/coronavirus/2019-ncov/vaccines/index.html [2] Polack, F. P., Thomas, S., Kitchin, N., Absalon, J., Gurtman, A., Lockhart, S., Perez, J. L., Walls, R., Lower, D., Ray, A., Thompson, M., & Flynn, P. J. (2021). Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine. New England Journal of Medicine, 385(17), 1603–1615. https://doi.org/10.1056/NEJMoa2104880 [3] Baden, L. R., El Sahly, H. M., Essink, B., Kotloff, K., Frey, S., Swerlick, R., & Omer, S. B. (2021). Efficacy and Safety of the Ad26.COV2.S Vaccine in Young Adults. New England Journal of Medicine, 385(1), 21–30. https://doi.org/10.1056/NEJMoa2034577 [4] Voysey, M., Clemens, S., Madhi, S. A., Laurie, J. A., Thava, M., Daniels, A. R., Folegá, A. J., Aley, S., Ferrara, L., & McLean, H. (2021). Safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) against SARS-CoV-2: a reanalysis of the phase 3 trial. The Lancet, 397(10284), 1329–1338. https://doi.org/10.1016/S0140-6736(21)00393-8 [5] Food and Drug Administration. (2021). FDA Authorizes Moderna COVID-19 Vaccine Booster Dose. https://www.fda.gov/news-events/press-announcements/fda-authorizes-moderna-covid-19-vaccine-booster-dose
- The COVID-19 booster shots, such as those from Moderna, have been widely studied and are instrumental in the fight against the coronavirus and its variants like Omicron.
- Scientific data shows that these booster shots can reduce the risk of contracting the SARS-CoV-2 virus by up to 99%, even though breakthrough infections can still occur, where a person tests positive after receiving the booster.
- Medical conditions like depression, nutrition, fitness-and-exercise, mental-health, and health-and-wellness should not be overlooked while considering the benefits of immunizationsvaccines like COVID-19 booster shots.
- A q-PCR test can detect the presence of SARS-CoV-2 even after receiving a booster shot, but a booster shot does not cause an infection.
- Side effects of the latest COVID-19 booster vaccines can vary among individuals, with common symptoms including pain, swelling, or redness at the injection site, fatigue, headache, muscle pain, joint pain, chills, nausea or vomiting, fever, and swelling of lymph nodes.
- Rare but notable side effects, such as myocarditis and pericarditis, can occur, especially in males aged 12 to 29 years. Although rates have decreased with subsequent boosters, the FDA continues to monitor these risks carefully.
- Updated boosters targeting newer variants, like the newest COVID-19 booster and the new bivalent booster, are designed to extend and broaden protection against the coronavirus and its variants.
