The Omicron variant of the SARS-CoV2 virus is intrinsically as severe as previous variants, , according to a preprint version of a large U.S.studythat counters assumptions in other studies that it was more transmissible but less severe.

The FDA announced it was limiting access to Johnson & Johnson’s Covid-19 vaccine because of the risk of a clotting disorder that was discovered weeks after the vaccine was first put into use in the spring of 2021.

Background: The speed of vaccine development has been a singular achievement during the COVID-19 pandemic, although uptake has not been universal. Vaccine opponents often frame their opposition in terms of the rights of the unvaccinated. We sought to explore the impact of mixing of vaccinated and unvaccinated populations on risk of SARS-CoV-2 infection among vaccinated people. Methods: We constructed a simple susceptible–infectious–recovered compartmental model of a respiratory infectious disease with 2 connected subpopulations: people who were vaccinated and those who were unvaccinated. We simulated a spectrum of patterns of mixing between vaccinated and unvaccinated groups that ranged from random mixing to complete like-with-like mixing (complete assortativity), in which people have contact exclusively with others with the same vaccination status. We evaluated the dynamics of an epidemic within each subgroup and in the population as a whole. Results: We found that the risk of infection was markedly higher among unvaccinated people than among vaccinated people under all mixing assumptions. The contact-adjusted contribution of unvaccinated people to infection risk was disproportionate, with unvaccinated people contributing to infections among those who were vaccinated at a rate higher than would have been expected based on contact numbers alone. We found that as like-with-like mixing increased, attack rates among vaccinated people decreased from 15% to 10% (and increased from 62% to 79% among unvaccinated people), but the contact-adjusted contribution to risk among vaccinated people derived from contact with unvaccinated people increased. Interpretation: Although risk associated with avoiding vaccination during a virulent pandemic accrues chiefly to people who are unvaccinated, their choices affect risk of viral infection among those who are vaccinated in a manner that is disproportionate to the portion of unvaccinated people in the population.

Massachusetts state senators and their staff were urged to wear masks in the Senate Chamber.

The news that Paxlovid did not work as a preventative for Covid doesn’t affect its primary use, experts say: treating people who are already sick.

No one’s actually sure.

New CDC research released Tuesday shows three out of every four American kids has been infected with COVID-19.

Over the weekend, the WHO published a much anticipated update on an unusual outbreak of hepatitis among children spanning several countries. On April 21, the outbreak resulted in the CDC releasing a Health Alert. The cause of the outbreak is currently unknown, creating quite the mystery for disease detectives.

The Biden administration announced a series of initiatives Tuesday aimed at increasing the use of antiviral pills to treat Covid-19, with a particular focus on Pfizer’s Paxlovid.

Travelers at Logan Airport and MBTA stations have expressed some confusion after a federal judge in Florida struck down the national mask mandate on airplanes and public transit.

Overall, in Massachusetts, positive cases jumped 36% from the week before, and cases in schools went up 24%.

People are desperate to return to life as normal, but the rising number of infections is a reminder that this pandemic isn’t over, says Christina Pagel, the director of UCL’s Clinical Operational Research Unit

Chasing scientific renown, grant dollars, and approval from Dr. Anthony Fauci, Peter Daszak transformed the environmental nonprofit EcoHealth Alliance into a government-funded sponsor of risky, cutting-edge virus research in both the U.S. and Wuhan, China. Drawing on more than 100,000 leaked documents, a V.F. investigation shows how an organization dedicated to preventing the next pandemic found itself suspected of helping start one.

The findings add further weight to the idea of mix-and-match boosting.

U.S. regulators on Tuesday authorized another COVID-19 booster for people age 50 and older, a step to offer extra protection for the most vulnerable in case the coronavirus rebounds. The Food and Drug Administration's decision opens a fourth dose of the Pfizer or Moderna vaccines to those people at least four months after their previous booster.

In a searing new report, the Black Coalition Against COVID details the immense toll the pandemic continues to take on Black communities, and calls for continued vigilance and action to prevent further losses.

Excess mortality and COVID.

Some have been used in hospitals, despite not being properly tested. But the pandemic could help make medical AI better.

Bad news if you're unvaccinated and think you have strong protection after omicron.

A fourth mRNA dose has been underway in Israel for a few months now. The U.K. recently started a fourth dose for people over 75 years old and coined it “spring boosters.” In Germany, those over 70 years old are eligible for a fourth shot of the mRNA series.

Humanities and Social Sciences Communications - Evaluation of science advice during the COVID-19 pandemic in Sweden

New evidence suggests anyone infected with COVID is at higher risk for heart issues—a risk that persists even in relatively healthy people long after the illness has passed.

An Italian study published on Tuesday suggests that efficient ventilation systems can reduce the transmission of COVID-19 in schools by more than 80%.

Long COVID continues to be a medical mystery, but some parts of the puzzle are falling into place. Learn more from intensivist Devang Sanghavi, MD.

The antiparasitic drug has received attention from celebrities including Joe Rogan.

With infections spiking in Europe and a variant on the rise, experts warn the U.S. should prepare for a Covid resurgence, even if it turns out to be minor.

The U.S. is at a pivotal moment. We can learn from our mistakes to prepare for future mutations and new public health threats. Or we can continue a “deadly cycle of panic and neglect”. Other countries, like South Korea and Vietnam, have had very effective responses to SARS-CoV-2. This was because of the lessons they learned from previous flawed responses, like MERS and SARS. By preparing, they were able to save hundreds of thousands of lives during this pandemic.

This Viewpoint discusses how differing political priorities and economic circumstances across the 50 US states has led to the country’s fragmented health policy, widening the gap across the states in health outcomes and life expectancy.

Case trends around the globe have made a u-turn and started increasing, specifically in Asian and European countries. The virus will continue to transmit and mutate, so a change in case trends shouldn’t be a surprise. We are also at a point in the pandemic where a rise in cases means something very different from country to country.