COVID update: Vaccinations, vitamin D and nanobodies

Getting vaccinated helps protects others who don’t

Older adults who get vaccinated against COVID-19 may also be protecting their unvaccinated family members. Researchers at the Helsinki Graduate School of Economics have found that the Pfizer-BioNTech and Moderna COVID-19 vaccines protect both vaccinated individuals and their unvaccinated adult household members against SARS-CoV-2 infections. The study used Finnish administrative datasets to examine the link between mRNA-based COVID-19 vaccines and infection risk among vaccinated individuals as well as their unvaccinated family members.

The study showed that the indirect protection for unvaccinated family members builds gradually over time. Two weeks after the recipient’s first dose, the spouses of vaccinated individuals showed 8.7% fewer cases of coronavirus than the spouses of unvaccinated individuals. Ten weeks after the first dose, the indirect effectiveness of vaccines for family members was up to 42.9%.

“Our study clearly shows that the vaccines reduce coronavirus infections in unvaccinated adults living in the same household. The results support the idea that vaccines reduce the risk of both getting infected and infecting others,’ said study investigator Mika Kortelainen, a Professor of Health Economics at the University of Turku in Finland.

This analysis was only possible because Finland has comprehensive, high-quality administrative data on its population. The study focused on healthcare workers as they were typically the only ones in their households to get a vaccination against coronavirus in Finland during the study period between January and March of this year.

Governments all over the United States and around the world are hoping to lift COVID-19 restrictions as vaccination coverage increases. These results provide new information on how vaccines affect infections among the unvaccinated, offering additional insight for decision-makers to design effective vaccination strategies, societal control measures, and travel recommendations for vaccinated individuals.

Vitamin D may not protect against COVID-19 susceptibility or severity

A new study by researchers at McGill University in Quebec, Canada, has found genetic evidence does not support vitamin D as a protective measure against COVID-19.

The ability of vitamin D to protect against severe COVID-19 illness is of great interest to public health experts, but has limited supporting evidence. To assess the relationship between vitamin D levels and COVID-19 susceptibility and severity, researchers conducted a study using genetic variants strongly associated with increased vitamin D levels. The authors analyzed genetic variants of 4,134 individuals with COVID-19, and 1.28 million without COVID-19, from 11 countries to determine whether genetic predisposition for higher vitamin D levels were associated with less-severe disease outcomes in people with COVID-19.

The results showed no evidence for an association between genetically predicted vitamin D levels and COVID-19 susceptibility, hospitalization, or severe disease, suggesting that raising circulating vitamin D levels through supplementation may not improve COVID-19 outcomes in the general population. However, the study had several important limitations, including that the research did not include individuals with vitamin D deficiency, and it remains possible that truly deficient patients may benefit from supplementation for COVID-19 related protection and outcomes. Additionally, the genetic variants were obtained only from individuals of European ancestry, so future studies will be needed to determine the relationship with COVID-19 outcomes in other populations.

Attacking COVID-19 in the nose

For those who can’t get vaccinated due to allergies or other health conditions, there may now be a new avenue of treatment. Researchers from the University of Pittsburgh School of Medicine have demonstrated that inhalable nanobodies targeting the spike protein of the SARS-CoV-2 coronavirus can prevent and treat severe COVID-19 in hamsters. This is the first time the nanobodies were tested for inhalation treatment against coronavirus infections in a pre-clinical model. Nanobodies are similar to monoclonal antibodies but smaller in size, more stable and cheaper to produce.

The scientists showed that low doses of an aerosolized nanobody named Pittsburgh inhalable Nanobody-21 protected hamsters from the dramatic weight loss typically associated with severe SARS-CoV-2 infection and reduced the number of infectious virus particles in the animals’ nasal cavities, throats and lungs by a million-fold.

“By using an inhalation therapy that can be directly administered to the infection site, the respiratory tract and lungs, we can make treatments more efficient,” said co-senior author Yi Shi, an assistant professor of cell biology at the University of Pittsburgh, Pittsburgh, Pennsylvania. “We are very excited and encouraged by our data suggesting that PiN-21 can be highly protective against severe disease and can potentially prevent human-to-human viral transmission.”

Previously, Shi’s team discovered a large repertoire of over 8,000 high-affinity SARS-CoV-2 nanobodies. From this repertoire, the scientists selected an ultra potent nanobody (Nb21) and bioengineered it to further maximize its antiviral activity. The resulting PiN-21 is by far the most potent antiviral nanobody that has been identified, according to the researchers’ review of published studies.

“COVID-19 is now a preeminent disease of the 21st century,” said co-author Doug Reed, an associate professor of immunology at Pitt. “Delivering the treatment directly to the lungs can make a big difference for our ability to treat it.”

Nanobodies and vaccines are complementary and do not compete with one another. Vaccines remain the best tool to stop the virus from spreading from person to person, but nanobodies will be useful to treat people who already are sick and those who can’t get vaccinated for other medical reasons. Promising early preclinical data, combined with the researchers’ extensive knowledge about rapidly identifying drug-quality nanobodies, suggest that this approach can provide a convenient and cost-effective therapeutic option to control the coronavirus pandemic.