Thread by @RetroReport

1/5 #COVID19 has introduced many people to an evocative new term, “super spreader”: a person who spreads infectious disease to an unusually large number of others. Super spreaders have been a factor in numerous epidemics and outbreaks in modern history. #LessonsFromHistory

2/5 One of the most notorious cases was Mary Mallon. Mallon worked as a cook in New York in the early 1900s, and for much of her life was an asymptomatic carrier of the typhoid bacteria. “Typhoid Mary” infected over 50 people, and was sent to live in isolation for over 25 years.

3/5 During the SARS epidemic of 2003, roughly half of the 8,000+ cases recorded were traced back to a single individual, who spent one night at a Hong Kong hotel. He infected over a dozen hotel guests, who in turn spread the disease to Canada, Singapore, and Vietnam.

4/5 During the smaller outbreak of MERS in South Korea in 2015, over 80% of all cases were traced back to five individuals. One patient was responsible for infecting 84 people alone. The spread largely occurred inside hospitals.

5/5 In recent months, there have been reports of events including religious services, birthday parties, funerals, and corporate conferences that resulted in clusters of infections. But it’s not yet clear how significant super spreaders have been to the #COVID19 pandemic overall.