There are COVID-19 incidents in which a single person likely infected 80 percent or more of the people in the room in just a few hours. But, at other times, COVID-19 can be surprisingly much less contagious. Overdispersion and super-spreading of this virus are found in research across the globe. A growing number of studies estimate that a majority of infected people may not infect a single other person. A recent paper found that in Hong Kong, which had extensive testing and contact tracing, about 19 percent of cases were responsible for 80 percent of transmission, while 69 percent of cases did not infect another person. This finding is not rare: Multiple studies from the beginning have suggested that as few as 10 to 20 percent of infected people may be responsible for as much as 80 to 90 percent of transmission, and that many people barely transmit it. [The Atlantic | more on the k factor]
In late February, drug company Biogen held its annual conference in Boston. The United States had fewer than 20 known COVID-19 cases at the time. But one of the roughly 200 attendees must have carried the virus. It triggered a big outbreak. At least 97 people who attended the conference, or lived in a household with someone who did, tested positive. The Biogen meeting had become a superspreading event. Eventually, the virus spread from the meeting across Massachusetts and to other states. A recent study estimates it led to tens of thousands of cases in the Boston area alone. [...] A study from India published in Science last month concluded that 8% of infected people caused 60% of the secondary cases; 70% of people did not pass the virus on to anyone else. [Science]
to date, none of the vaccines being developed for the U.S. market has been proven to be effective in preventing Covid-19 disease. [STAT]
We analyzed all-cause mortality among adults ages 25-44 during the COVID-19 pandemic in the United States. We find that COVID-19 has likely become the leading cause of death (surpassing unintentional overdoses) among young adults aged 25-44 in some areas of the United States during substantial COVID-19 outbreaks.
Recent findings of heart involvement in young athletes, including sudden death, have raised concerns about the current limits of our knowledge and potentially high risk and occult prevalence of COVID-19 heart manifestations.
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Achieving herd immunity without an effective vaccine would result in widespread fatalities. [...] "And remember, [Michael Osterholm, a renowned infectious-disease expert, said,] when we talk about getting to 50%–70% protection, we're talking you can get there with disease — but if that happens, there will be lots of deaths, a lot of serious illnesses — or we can try to get there with vaccination, and postponing the number of people who get sick until we have the vaccines available. 5o%–70% just slows down transmission, it doesn't stop it. So this virus is going to keep looking for wood to burn for as long as it can ... so, our goal is to get as many people protected with vaccines" [Axios]
A man caught coronavirus twice—and it was worse the second time -- That makes him the fifth recorded person to have caught the coronavirus twice—and raises more questions about how immunity might work.
Slovakian Prime Minister Igor Matovic announced plans Saturday to test everyone aged 10 years and over in the country for Covid-19 [...] “testing will be free-of-charge” for the population of 5.4 million. The campaign is expected to take place over two weekends starting at the end of October. It is not yet known whether participation will be mandatory. [CNN]
Coronavirus transmission is slipping out of control in Belgium, Health Minister Frank Vandenbroucke said Sunday, on the eve of new restrictions in the country. “We are really very close to a tsunami,” he warned, speaking to broadcaster RTL. “We no longer control what is happening.” New restrictions are set to take effect on Monday, including the closure of all bars and restaurants, and a midnight curfew nationwide. [Politico]
In a young, low-risk population with ongoing symptoms, almost 70% of individuals have impairment in one or more organs four months after initial symptoms of SARS-CoV-2 infection. [MedRxiv]
In two early studies, researchers said some patients showed signs of healing just weeks after leaving the hospital. [...] about 80 percent of patients have mild to moderate symptoms, 15 percent develop a severe form of the disease and roughly five percent like Ms. Coissieux escalate to critical. [...] Ms. Coissieux, 78, was sent to a nearby pulmonary rehabilitation clinic, Dieulefit Santé, where a physical therapist taught her breathing exercises to help restore her lungs and the muscles involved in breathing. When she went home three weeks later, Ms. Coissieux could walk close to 1,000 feet, albeit with a walker. As she continued exercising at home, she grew stronger. “Now I can walk 500 meters with no walker,” or about 1,600 feet. [NY Times]
California biotech company Vaxart, which is working on a Covid-19 vaccine, is under federal investigation and is being sued by a number of investors for allegedly exaggerating its involvement in the US government's Operation Warp Speed program for developing Covid-19 vaccines and treatments. In June, Vaxart issued a press release that said "Vaxart's Covid-19 Vaccine Selected for the US Government's Operation Warp Speed." The news helped propel Vaxart's stock price to nearly $17, up from approximately $3, and hedge fund Armistice Capital, which partly controlled Vaxart, sold shares for a profit of more than $200 million, according to its SEC filings. A few weeks before the announcement, Vaxart granted amendments to the warrants agreements, which allowed Armistice to sell almost all of their stock, which they did once the stock price skyrocketed. In July, the US Department of Health and Human Services (HHS) told the New York Times that it had not entered into a funding agreement or negotiations with Vaxart. Vaxart has not been chosen by Operation Warp Speed to receive research funding, but instead had limited involvement, HHS told the New York Times. Vaxart's vaccine, an oral tablet, was only involved in preliminary studies on primates sponsored by Warp Speed. [CNN]