The Centres for Disease Control and Prevention (CDC) has updated its guidelines for gatherings in the US, though has failed to distinguish between indoor and outdoor events.

As lockdown measures are now largely lifted, the CDC lists several considerations for event planners, but has left the decisions for planning primarily up to local authorities.

It added that “these considerations are meant to supplement – not replace – any state, local, territorial, or tribal health and safety laws, rules, and regulations with which gatherings must comply.”

The recommendations encourage event goers to wear masks to reduce the spread at large events, as well as other gatherings. It also advocates for frequent hand-washing, keeping more than six feet away from other people, and limiting the amount of time spent with other people.

Gatherings mentioned in the guidance include concerts, festivals, conferences, parades, weddings and sporting events.

The CDC advises “the higher the level of community transmission in the area that the gathering is being held, the higher the risk of COVID-19 spreading during a gathering.”

The guidance also pushes for the regular cleaning of restrooms, the need for ventilation, and modifying event space layouts with physical barriers to ensure social distancing.

Event organisers are being urged to post signs at the event promoting protective measures, as well as broadcasting regular announcements on reducing the spread.

The modified layouts section includes details on limiting attendance or hosting smaller events in larger rooms, as well as using multiple entrances and exits and says to “prioritise outdoor activities where social distancing can be maintained as much as possible.”

CDC Director Robert Redfield said during the morning briefing: “I know people are eager to return to normal activities and ways of life. However, it’s important that we remember this situation is unprecedented and the pandemic has not ended.”

However, the advice does not detail the difference between indoor and outdoor events, which has led to Mark Levine, the chair of the New York City Council health committee, pointing out this omission on Twitter.

In other countries, guidelines and reopening schedules have been different for indoor and outdoor events. For example, in Australia last week, the government moved to allow outdoor ticketed events of up to 10,000 attendees from July, while the current 100-person limit on indoor events will also be lifted next month.

The US has reported more than two million confirmed cases of COVID-19 and 114,000 deaths, and the CDC forecasts an additional 10,000 to 24,000 deaths by July 4.

The country was largely shut down for about six weeks in March and April, but has been gradually reopening and easing measures since then.

However, some states, such as California and Texas, have begun to see spikes in the number of cases likely due to the loosening of stay-at-home rules.

“If cases begin to go up again, particularly if they go up dramatically it’s important to recognise that more significant mitigation efforts like what was implemented back in March may be needed again,” said Jay C. Butler, M.D., the CDC’s deputy director of infectious diseases and COVID-19 response incident manager.

“That is a decision that really needs to be made locally based on what is happening within the community regarding disease transmission.”

It should be noted that Dr. Mark Ghaly, California’s Secretary of Health and Human Services, said that a rise in overall case counts is linked to an increase in testing as more infections are identified among those who are not seriously ill.