A study conducted by US and Austrian researchers has identified SARS-CoV-2 variants with resistance to widely used antiviral treatments.

The study, published yesterday in Science Advances, found that several naturally occurring variants of M^pro, the main protease of SARS-CoV-2 that is essential for virus replication and is the main target of antivirals, carry amino acid mutations that confer resistance to nirmatrelvir (the main component of Paxlovid) and ensitrelvir, which received regulatory approval in Japan in February. Phylogenetic analysis indicates that these variants predate the use of these drugs, have appeared multiple times independently in different parts of the world, and are capable of spreading.

The authors of the study say that while it's unclear what magnitude of resistance will be needed for treatment failure in a clinical setting, ongoing SARS-CoV-2 transmission, continuous evolution of the virus, and widespread use of the drugs means the variants may serve as an "evolutionary stepping stone" that could develop into variants with full drug resistance. They say this could be thwarted by developing new antiviral drugs with different resistance profiles and by using a multi-drug approach.

"We are optimistic that ongoing studies will develop additional compounds to avoid cross-resistance and help combat the current COVID-19 pandemic and future coronavirus outbreaks," Reuben Harris, PhD, co-director of the University of Minnesota's Antiviral Drug Discovery Center, said in a press release.

Health officials in Equatorial Guinea have confirmed four more Marburg virus cases in the country's outbreaks, raising the confirmed total to 13, the health ministry said yesterday on Twitter. Two more of the lab-confirmed patients died from their infections, raising the fatality count to nine.

Earlier in the outbreak the country also reported 20 probable cases, all fatal.

Two patients are currently hospitalized with mild symptoms, and one of the infected people has recovered. So far, 825 contacts have been identified for monitoring.

Equatorial Guinea's Marburg virus outbreak, its first, began in January. Cases have been reported across a more than 100-mile area, including in two cities, raising worries about wider spread, especially in more populated areas.

The outbreak is Africa's third since 2022. Tanzania is also battling its first Marburg virus outbreak, but so far there doesn't appear to be any epidemiological connections between the two events. The virus is known to jump from fruit bats to people, and human-to-human spread can occur after contact with an infected person's body fluids.

A study of about 150 babies born to women who had COVID-19 during pregnancy found growth patterns that have been linked to developing obesity and other health problems. A research team based at Massachusetts General Hospital (MGH) reported their findings yesterday in The Journal of Clinical Endocrinology and Metabolism.

For their longitudinal cohort study, they examined data on 149 babies who had exposure to COVID-19 during the mother's pregnancy, comparing it with data on 127 babies who weren't exposed during pregnancy. They focused on weight, length, and body mass index (BMI) data from health records at 0, 2, 6, and 12 months. The team adjusted for several factors, including maternal age, ethnicity, and breastfeeding.

Babies born to mothers who had been sick with COVID had lower BMIs at birth, but greater BMIs from birth to 12 months, marked by a steep progressive rise during infancy. In contrast, the unexposed babies typically experienced a decline in BMI in the first 6 months that rebounded to baseline by 12 months.

Researchers said lower birth weight and faster weight gain during the first year of life may be harbingers of cardiometabolic problems later in life and that the findings support the need for close monitoring.

In a press release from The Endocrine Society, Andrea Edlow, MD, a study coauthor who is at MGH, said, "Larger studies with longer follow-up duration are needed to confirm these associations."

• A steep COVID-19 rise in India, which is experiencing its highest level in 6 months, has prompted stepped up testing in the capital city of New Delhi, Reuters reported today. The local government held an emergency meeting to discuss rising cases and has urged people in New Delhi to wear masks if they have flulike symptoms or are in hospital settings.
• Following a similar move by the House, the Senate yesterday—along party lines—passed a bill that would end the nation's public health emergency for COVID-19, CBS News reported. In late January, the White House announced that it would end the national emergencies for COVID on May 11, rejecting a Republican House proposal to end them abruptly. A White House official told CNN that President Biden would sign the measure while working with agencies to wind down the emergency and give as much notice to people impacted by the action. The public health and national emergencies have been in effect since 2020 and have given federal officials more funding and regulatory flexibility to respond to the pandemic.
• China has announced a plan to do random and spot checks at health facilities, part of an effort to shore up COVID data on severe illnesses and deaths, Reuters reported yesterday. Following the surge that began in late 2022, global health officials had raised concerns about incomplete and underreporting of China's COVID metrics.