Once exposed to Covid, a person can infect and kill others.

Judged by scientific understanding as of 2020-11-17. True: authoritative public-health sources (CDC, WHO, peer-reviewed research) show that a person infected with SARS-CoV-2, including one without symptoms, can pass it to others, and that such transmission can cause fatal Covid-19. Mostly true: this holds, but the claim's wording overstates it by implying that every exposure leads to infection or transmission. Mostly false: the sources showed that exposed or infected people rarely transmit, or that transmission rarely causes death. False: the sources showed that infected people do not transmit the virus or that Covid-19 is not fatal.

Set before the research began.

1. E1 What the data say about asymptomatic COVID infections Nature · 18 November 2020

   “People without symptoms can pass on the virus, but estimating their contribution to outbreaks is challenging.”

2. E2 Listings of WHO's response to COVID-19 World Health Organization · 29 June 2020

   “WHO reported on evidence of transmission from symptomatic, pre-symptomatic and asymptomatic people infected with COVID-19, noting that transmission from a pre-symptomatic case can occur before symptom onset.”

3. E3 Listings of WHO's response to COVID-19 World Health Organization · 29 June 2020

   “it is possible that there may be individuals who are asymptomatic that shed virus, but we need more detailed studies around this to determine how often that is happening and if this is leading to secondary transmission”

4. E4 Listings of WHO's response to COVID-19 World Health Organization · 29 June 2020

   “The Director-General said that Europe had become the epicentre of the pandemic with more reported cases and deaths than the rest of the world combined, apart from the People’s Republic of China.”

WHO reported evidence of transmission from symptomatic, pre-symptomatic and asymptomatic people infected with COVID-19 (E2). Nature reported that people without symptoms can pass on the virus (E1). WHO also recorded large numbers of COVID-19 deaths (E4), so Covid-19 was fatal and transmission could lead to deaths. However, the claim says that "once you are exposed" you can infect others. That treats exposure as if it were infection, and E3 notes that how often asymptomatic shedding leads to onward transmission was still uncertain, so the wording overstates the science somewhat.