A study published in Nature Communications last week describes how markers of brain injury are present in the blood months after COVID-19 infection, despite normal inflammation blood tests.

The findings, which come from research teams at the University of Liverpool and King’s College London, add to the complicated picture of how COVID-19 can cause a range of neurologic symptoms.

During the COVID-19 pandemic it became apparent that neurological complications were occurring in a significant proportion of hospitalized patients.

"During the COVID-19 pandemic it became apparent that neurological complications were occurring in a significant proportion of hospitalized patients and even in those with mild COVID-19 infection," Benedict Michael, PhD, principal investigator, said in a study press release.

The present study looked at blood samples from 800 patients hospitalized with COVID-19 from across England and Wales, half of whom had new neurologic conditions. Researchers looked at blood levels of serum inflammatory proteins (cytokines), antibodies, and brain (neuroglial) injury proteins.

The authors found that in the early convalescent phase (less than 6 weeks post-infection), markers were elevated in participants recovering from COVID-19, with no differences between those who had or had not experienced a neurologic complication. After 6 weeks, elevated markers were seen only in participants who suffered neurologic symptoms in the acute phase of illness.

"These brain injury markers are associated with dysregulated systemic innate and adaptive immune responses in the acute phase of the disease, and suggest that these may represent targets for therapy," the authors said.

A new report published in Open Forum Infectious Diseases demonstrates that, despite the proven effectiveness of Paxlovid and molnupiravir against severe COVID-19 outcomes, uptake of these two antivirals remains low among Americans with COVID.

The report focused on antiviral uptake among vaccinated Americans who contracted COVID-19 between December 2021 and October 2022. Uptake of oral nirmatrelvir/ritonavir (NMV/r or Paxlovid) and molnupiravir (MOV) increased as the study period progressed, but was low overall.

Paxlovid uptake was 13.6% (95% confidence interval [CI], 11.9% to 15.2%) among 1,594 participants and MOV uptake was 1.4% (95% CI, 0.8% to 2.1%) among 1,398 participants. Paxlovid use increased over time, from 1.9% during December 2021 to March 2022 to 25.3% between August and October 2022.

Over the course of the study, most participants were eligible for antiviral use (NMV/r: 85%; MOV: 84%), with uptake higher among those 65 and older. Use of Paxlovid was 30.2% (95% CI, 22.2% to 38.2%) among adults 65 and older, and was also higher among those who self-reported a history of long COVID.

There are a number of factors that may contribute to low antiviral uptake among those including low awareness of antivirals.

"There are a number of factors that may contribute to low antiviral uptake among those including low awareness of antivirals, healthcare disparities, and barriers to healthcare and prescription access," the authors said. "A population-representative study in NYC found that 44% of adults were unaware of antivirals."

• China has reported a fatal H5N6 avian flu case involving a 33-year-old woman from Sichuan province who got sick in October after visiting a live poultry market, according to a statement from Hong Kong's Centre for Health Protection (CHP). Her infection marks China's seventh H5N6 cases of the year and the country's 88th since the virus was first found in humans in 2014. The virus is known to circulate in poultry in China and a few other Asian countries. In other avian flu developments, in a weekly update today the CHP reported two more H9N2 cases from China, both from Sichuan province. One patient is a 1-year-old boy, and the other is a 74-year-old woman. Both were sick in November. China has reported five H9N2 cases over the last 6 months. The virus is known to circulate in poultry and typically affects children, causing a mostly mild disease.
• Global dengue cases have risen markedly in the past two decades, posing substantial public health challenges, the World Health Organization (WHO) said in a December 21 outbreak notice. Cases rose tenfold across 129 countries between 2000 and 2019. Activity slightly declined between 2020 and 2022, due to COVID impacts, but a surge in 2023 has pushed cases to a near-record high, with more than 5 million cases, more than 5,000 deaths, and spanning more than 80 countries in five WHO regions. Factors include vector distribution changes, climate change, El Nino weather pattern consequences, and fragile health systems.
• Three African nations—Chad, the Democratic Republic of the Congo, and Nigeria—reported more polio cases, all involving vaccine-derived types, the Global Polio Eradication Initiative (GPEI) said in its latest weekly update. Chad reported five circulating vaccine-derived poliovirus type 2 (cVDPV2) cases from five different provinces, putting its total for the year at 50. The DRC reported six cVDPV2 cases, making 116 for the year, and three infections involving circulating vaccine-derived poliovirus type 1 (cVDPV1), lifting that number to 95 for 2023 and the total for 2022 to 150. Also, Nigeria reported five cVDPV2 cases, boosting its total for 2023 to 62.