Covid rebounds at the White House; Omicron-targeting boosters coming at end of year

High transmission almost everywhere but vaccines, treatments keeping hospitalizations and deaths relatively low. My take: keep your masks handy.

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President Biden has Paxlovid rebound but no symptoms

The White House physician’s letter that reached reporters’ inboxes around 2:30 PM EDT on Saturday was unexpected, but the president’s “rebound” positive Covid test was not surprising. According to the White House, the president has no symptoms but tested positive Saturday morning and resumed isolation, according to protocols.

Key point: Masks, vaccines, boosters, frequent testing and avoiding indoor crowds are the best ways to prevent infection. Paxlovid is one of several therapeutics that can help prevent severe illness or death if infection occurs.

The number of people who experience Covid rebound after taking Paxlovid is thought to be around 5%, but the rate is not clearly established. Some, like NIH Director Dr. Tony Fauci, experience significant symptoms on rebound, usually for a short time. Others, like President Biden, test positive and may be contagious but report no symptoms. There is still much to this disease that we don’t know.

Even with rebound, Paxlovid appears to be overwhelmingly effective at preventing the most severe cases of Covid-19 disease. However, lab studies suggest that the Covid virus may be capable of developing resistance to Paxlovid, much the way variants are finding their way around vaccine- or infection-induced immunity.

Ventilation prevents Covid spreading indoors

White House Covid-19 Coordinator Dr. Ashish Jha says that opening windows, turning on fans or air conditioning are among the best ways to reduce Covid risk when indoors with other people.

• Students in classrooms with high rates of mechanical ventilation have up to 80% lower risk of Covid infection, according to a study done in Italy. The researchers found that infection rates were lowest in classrooms with greater than 5 air changes per hour (ACH,) which is higher than typical systems.

• You can make your own highly effective air purifier with an inexpensive box fan, some duct tape and off-the-shelf HVAC filters. Find out more at this link:

  

• Previous research also associates improved ventilation with higher performance on cognitive tasks.

• The results in any specific place will depend on current rates of Covid-19 transmission plus other factors such as the number of people in each room, vaccination status, and whether people wear masks.

Moderna, Pfizer rushing to make omicron-specific boosters

The federal government has ordered over 170 million doses of “bivalent” Covid-19 vaccine doses for use in late Fall and Winter. The vaccines by Moderna and Pfizer will add an omicron-specific component to the existing vaccines.

This article by my former colleague Rita Rubin provides a thorough review of the debate among FDA advisors about this approach — and how scientists and regulators are making these complex decisions.

Covid’s origin still thought to be Wuhan live animal market

Scientists report in the journal Science on why data and other evidence points to a Wuhan, China, market as the source of the Covid-19 outbreak, not a lab in Wuhan or anywhere else. The research team shows that coronavirus-susceptible species were at the market, environmental samples with the virus were taken from close to where vendors were selling those animals, and 55 of the first 168 known Covid-19 cases were associated with the market. The team says the precise origin cannot be established but the animal-to-human jump occurring at this market fits the observations, recorded data, and known biological mechanisms.

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