Many governments placed restrictions on large gatherings during the COVID-19 pandemic. These events have the potential to be a venue for COVID-19 transmission and can lead to increased cases, hospitalizations, and deaths. During a large gathering many households interact, sometimes from different parts of a region or country, which can contribute to spreading disease.

However, not all large gatherings may lead to increases in COVID-19 cases. Some large gatherings take place outdoors with protective health measures such as physical distancing, mask wearing, hand sanitizing. For example, the 2020 Black Lives Matter protests in the United States did not lead to spikes in COVID-19 community transmission. This may be because of public health precautions taken during the protests, and the participants' risk-avoiding behaviors after the protests, according to a study by the National Bureau of Economic Research.

Experts anticipate that some large gatherings in the future may include requests for participants to be vaccinated, to reduce the risks of transmission. This model is similar to how live attendees were required to be fully vaccinated for VAX LIVE: The Concert to Reunite the World.

Many experts are most concerned about large gatherings during which public health precautions are not taken. During "anti-lockdown" protests, participants may be less likely to engage in physical distancing, mask wearing, and hand sanitizing. Studies have found that some "anti-lockdown" protests led to an increase in COVID-19 cases afterwards. For example, the seven-day infection rate rose significantly following two Querdenken demonstrations in Germany and up to 21,000 COVID-19 infections could have been prevented, according to analysis by the Leibniz Centre for European Economic Research and Humboldt University of Berlin.

Cell phone data suggested "anti-lockdown" protests in the United States (ex. Operation Gridlock in Denver) could have spread COVID-19 infections across state lines, according to data from the Committee to Protect Medicare. Leaders of "anti-lockdown" protests who tested positive for COVID-19 have also stated that they would continue to attend future protests, against the advice of doctors and public health professionals.

Other high-risk events include private gatherings where public health precautions are not taken. For example, some California counties in the United States reported spikes in COVID-19 cases in November 2020 after large Halloween parties. There is often a lag between a super-spreading event and visible increases in COVID-19 cases.

Even when certain large gatherings are likely responsible for transmitting new cases of COVID-19, it can be difficult to see a spike following the gathering when COVID-19 cases have been falling overall, thanks to protective public health measures and increases in vaccinations.

Often there is not enough data being collected to see clearly how much COVID-19 cases may have risen after specific events. For example, public health agencies may not track people's attendance at particular gatherings to respect privacy. Lacking that data, researchers may analyze statistics in the locations where certain events occurred, use anonymized cell phone location data, and rely on other methods.

There have been posts circulating on social media that question why some large gatherings have not been followed by a rise in COVID-19 cases. Some of these posts question the risks of protests against public health precautions, including "anti-lockdown" protests in the United Kingdom in spring 2021. In the United Kingdom, COVID-19 cases have been declining overall and over half of the population has received at least a first dose of a COVID-19 vaccine.

Experts continue to encourage people to respect public health protections because the COVID-19 pandemic still poses risks to human life. For example, 38.5% of new COVID-19 cases in the United Kingdom as of May 27, 2021 were of the fast-spreading B.1.617.2 variant first identified in India, according to Public Health England.