(1/4) Study of #COVID19 in Hong Kong from January to April, showing that the epidemic was characterised by superspreading events. Just 19% of infections were responsible for 80% of secondary cases, and 69% of people did not infect anyone. nature.com/articles/s4159…
(2/4) However, interventions in place included school closures, some people working from home, bans of mass gatherings, and near-universal mask wearing.
Had these interventions not been in place, even more superspreading may have occurred.
(3/4) The majority of cases (51%) were linked to one of 137 clusters. The largest cluster (106 cases) was associated with 4 bars, the 2nd largest (22 cases) to a wedding, and the 3rd largest (19 cases) to a temple.
Musicians are thought to have spread the virus between the bars.
(4/4) Because people are often infectious before they develop symptoms, isolating confirmed cases may only be of limited benefit.
However, quarantining the contacts of known cases was highly effective in breaking transmission chains.
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Policymakers shouldn’t be trying to manage COVID-19 as if it were seasonal influenza. It’s not and never will be. SARS-CoV-2’s greater transmissibility leads to faster viral evolution. This means waves of disease throughout the year, rather than a single winter COVID season. 🧵
Thanks to vaccination, COVID-19 is far less deadly than it used to be. But a virus doesn’t have to put people in hospital to be disruptive. Leaving aside the issue of long COVID, frequent waves of infection will grind down economic productivity.
Many seem to believe COVID-19 will become seasonal, but why should it? Influenza generally isn’t very transmissible and infects a small number of people each year. There’s plenty of time to design vaccines based on what’s happening in the opposite hemisphere of the globe.
(1/6) Respiratory viruses are much more likely to spread indoors than outdoors, but outdoor super-spreading events can still occur if the conditions are right.
A new study describes a SARS-CoV-2 outbreak affecting 131 people at a night market. 🧵
(2/6) The outbreak happened when a family of 3 people infected with the omicron BA.5.2 variant visited a night market in Zhejiang Province, China, in July 2022. They spent 1 hour and 4 minutes at the market.
(3/6) On the evening of the outbreak, it was warm (27 degrees Centigrade), humid, and there was very little wind.
Most of the market stalls had big umbrellas and it was crowded. The market had a capacity of 5,000 people.
Could future vaccines be administered via a patch? Researchers have developed skin patches containing tiny “microneedles” made of sugar and salt which dissolve on contact with skin, painlessly administering a vaccine in the process. 🧵 asm.org/Articles/2022/…
A key advantage of this technology is that a vaccine patch can induce a special kind of immunity in the skin, known as mucosal immunity, which can prevent infection and transmission. Injectable vaccines may only prevent severe disease.
Skin patch vaccines are also likely to have fewer side effects because of the way they slowly dissolve over minutes to hours.
This slow-release formula is less likely to trigger flu-like symptoms that sometimes follow injectable vaccines.
Imagine if you could rapidly detect COVID-19 in public places by testing the air. Now you can! Researchers have developed a groundbreaking new air monitor that can detect the presence of an infected person in as little as 5 minutes. 🧵 nature.com/articles/s4146…
The compact device, which measures 12 x 10 x 10 inches, has a sensitivity of ~80% and can detect as few as 7 viral RNA copies per cubic metre of air with a resolution of 5 minutes.
The major limitation of the prototype is noise (75-80 dB; similar to heavy traffic), although the researchers are trying to develop a quieter version with low-noise motors and/or sound-proofing.
A representative survey of US adults in mid-2022 found that 7% had long COVID (4-week definition; using questions developed by the UK’s Office for National Statistics).