That has been the case for Trump, who announced Friday he had the coronavirus amid a growing cluster of positive tests among White House staff, aides and allies.

Earlier in the pandemic, that was also true for members of Iran’s parliament - more than 10 percent of whom had contracted the virus by early March.

Within another month, 31 of its 290 members had confirmed testing positive, including the parliament’s speaker Ali Larijani. In the early days of the pandemic, the virus struck the head of Iran’s emergency medical services and a deputy health minister. The virus also killed a key adviser to Iran’s supreme leader, Ayatollah Ali Khamenei, as well as several other senior political figures.

Much more is now known about how the virus spreads than when reports of a mysterious pathogen began circulating the globe in early 2020.Indoor and poorly ventilated gatherings where people are crowded together and talking loudly are particularly risky, scientists now agree. Men and those above age 60 are at higher risk for complications.

People who are asymptomatic can pass on the virus, while “superspreaders” - people who heavily shed the virus - account for a majority of known transmission. And masks, public health experts repeatedly recommend, can curb the spread of the virus, in addition to frequent hand washing and social distancing.

Iran shut its parliament on Feb. 25, six days after confirming its first infections and fatalities. But with an incubation period of two weeks - and sometimes even more - it appears that move was already too late to stem the virus’s march through the country’s echelons of power once an outbreak had found its way in.

In the months since, parliaments and congresses around the world have gone virtual or opted for a hybrid model to prevent these kinds of superspreading events. Occasionally, government buildings have temporarily shut and members ordered into quarantine after one of their own tests positive. In Sudan, 10 members of the country’s coronavirus task contracted the coronavirus in May.

Before Trump’s infection, British Prime Minister Boris Johnson was among the most high-profile world leaders to battle covid-19, the disease caused by the virus, which nearly killed him.

In the spring, Iran was among the region’s hardest hit country by the coronavirus. Critics accused the government of covering up the severity of outbreaks, as hospitals, already crumbling amid an economic crisis, struggled to provide care.

When its parliament reopened in April, strict social distancing rules were put in place. State-run television displayed images of some members huddled together nonetheless.