Whether you should get tested after holiday gatherings depends a lot on factors such as the level of transmission of Covid-19 within your region, the vaccination status of all the attendees, the likelihood of Covid-19 in any of the attendees, and your threshold for risk of either contracting or transmitting of Covid-19 to others, particularly immunocompromised persons. 

The following discussion assumes a scenario that is common to most indoor holiday gatherings: 1. You are getting together with people outside of your household; 2.  You or your family members don’t wear a face mask at all or certainly not all the time during the gathering; and 3. You find it impossible or don’t wish to socially distance from others during the get-together.^1,2

First, let’s start with 2 situations where you should get tested following a holiday get-together, irrespective of your (or the attendees’) vaccination status: 1. if you have symptoms of Covid-19; and 2. If you were in close contact of an infected person (ie, commonly defined as within 6 feet of that person for a minimum of 15 minute during a 24-hour period).³

In the absence of known exposure or symptoms, you should consider getting tested if you are not fully immunized since you will be at higher risk of contracting and transmitting Covid-19 to others as long as there is still significant Covid-19 transmission in the region.  In contrast, if you and other attendees are fully immunized already, routine testing for Covid-19 after the gathering is hard to justify given the effectiveness of FDA-authorized Covid-19 vaccines and the costs and impracticalities associated with routine testing of millions of fully vaccinated persons.  

It goes without saying that holiday gatherings with family members outside of one’s immediate houseshold is not a zero-risk proposition for contracting or transmitting Covid-19 because people can have no symptoms and be infectious and vaccinated individuals can on occasion become infected.   Even the tests are not perfect. However, if you are concerned that you might have been exposed to Covid-19  and knowledge of a negative Covid-19 test (with its inherent limitations) gives you peace of mind, you should consider getting tested. The over-the-counter rapid Covid-19 tests may be particularly useful in assessing the likelihood of being contagious.⁴

For further recommendations on when you should consider getting tested for Covid-19 in general, I highly recommend an NIH-sponsored online calculator called “When to Test”.  This calculator is based on mathematical modelling that takes into account an individual’s vaccination status, transmission rates in the geographic area, and mitigation behaviors (eg, masks and social distancing).¹

Bonus Pearl: Did you know that persons with Covid-19 are considered infectious 2 days before they develop symptoms or 2 days before the date of their positive test if they don’t have symptoms?⁵

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References:

1. When to test offers free online tool to help individuals make informed Covid-19 testing decisions. https://www.nih.gov/news-events/news-releases/when-test-offers-free-online-tool-help-individuals-make-informed-covid-19-testing-decisions. Accessed November 26, 2021.
2. Covid-19 testing overview. https://www.cdc.gov/coronavirus/2019-ncov/symptoms-testing/testing.html. Accessed November 26, 2021.
3. Covid-19. https://www.cdc.gov/coronavirus/2019-ncov/php/contact-tracing/contact-tracing-plan/appendix.html#contact. Accessed November 26, 2021.
4. Schuit E, Venekamp RP, Pas SD, et al. Diagnostic accuracy of rapid antigen tests in asymptomatic and presymptomatic close contacts of individuals with confirmed SARS-CoV-2 infection: cross sectional study. BMJ 2021;374:n1676.  https://www.bmj.com/content/374/bmj.n1676
5. Quarantine and isolation. https://www.cdc.gov/coronavirus/2019-ncov/your-health/quarantine-isolation.html#:~:text=Get%20tested%205%2D7%20days%20after%20their%20first%20exposure.,the%20person%20with%20COVID%2D19. Accessed November 26, 2021.

Disclosures: The listed questions and answers are solely the responsibility of the author and do not necessarily represent the official views of Mercy Hospital-St. Louis, Massachusetts General Hospital, Harvard Catalyst, Harvard University, their affiliate academic healthcare centers, or its contributors. Although every effort has been made to provide accurate information, the author is far from being perfect. The reader is urged to verify the content of the material with other sources as deemed appropriate and exercise clinical judgment in the interpretation and application of the information provided herein. No responsibility for an adverse outcome or guarantees for a favorable clinical result is assumed by the author. Thank you!