Deer infections, vaccination boosts and prediction of ‘breakthrough’ COVID cases

The coronavirus rages on the American common deer

One third of white-tailed deer (Odocoileus virginianus) in the northeastern United States have antibodies to SARS-CoV-2 – a sign that they have been infected with the virus.

The results, reported in a July 29 prepublication (JC Chandler et al. preprint on bioRxiv https://doi.org/gmc8t6; 2021), represent the first detection of widespread exposure to the virus in a population of wild animals.

There are concerns about the emergence of new animal “reservoirs” – animal populations that harbor SARS-CoV-2. Previous lab experiments have shown that white-tailed deer can become infected with the coronavirus and pass it on to other deer. In the wild, animals live in herds, which could facilitate the spread of the virus.

Scientists at the U.S. Department of Agriculture in Fort Collins, Colo., And Ames, Iowa, tested 385 deer blood samples collected as part of routine wildlife monitoring between January and March 2021 in Michigan, the Pennsylvania, Illinois and New York State. They found that 40% of the samples contained SARS-CoV-2 antibodies, which are produced in response to infection. None of the deer interviewed showed signs of disease.

Testing of archived samples also revealed antibodies in three samples from early 2020, when SARS-CoV-2 began circulating in the United States. In total, a third of the samples from 2020 and 2021 had antibodies to the virus.

It is not known how the deer were exposed. This could have been through contact with people, other animals or even contaminated sewage.

Researchers say rapid exposure of large numbers of animals to the virus is cause for concern, but more studies are needed to assess whether deer can infect each other – and other species – in nature. “It’s an intriguing observation but one that should always be interpreted with caution,” says Aaron Irving, an infectious disease researcher at Zhejiang University in Haining, China.

Texting May Increase COVID Vaccinations

A short text message reminding people to reserve a COVID-19 vaccine can increase vaccination rates by several percentage points, according to a study of more than 90,000 people in California.

A reminder sent a day after individuals became eligible for appointments and vaccination rates increased by 6 percentage points and about 3.6 percentage points, respectively, compared to the rates in one group distinct which did not receive the callback (H. Dai et al. Nature https://doi.org/gqtk; 2021). A second reminder to those who still had not made an appointment for vaccination a week later increased appointments and injections by an additional 1.7 and 1.1 percentage points, respectively.

The researchers tested reminder texts made up of two different formulations, which were sent to members of a large healthcare system. Some people have received a “basic” reminder that they can get the vaccine. Others received a “ownership” reminder telling them that a vaccine “had just been made available”, with instructions on how to “claim” their dose.

The ownership reminder was more effective: When it was sent a day after people became eligible for the vaccine, it increased recipient vaccination rates by about 4.1 percentage points, up from an increase 3 percentage points for the “basic” recall.

These small gains, if applied to a large population, could speed up the vaccination of millions of people, according to the authors.

Blood marker predicts groundbreaking COVID cases

People fully vaccinated against COVID-19 are less likely to be infected with the coronavirus if they have relatively high levels of antibodies blocking the virus, according to a study of more than 10,000 health workers who have received the vaccine Pfizer-BioNTech (M. Bergwerk et al. N. Engl. J. Med. https://doi.org/gmc77b; 2021).

The analysis adds to a growing body of evidence that a person’s levels of “neutralizing” antibodies, which prevent SARS-CoV-2 from infecting cells, predict whether that person will be infected.

A robust predictive marker could help regulators approve new vaccines without requiring large clinical trials. It could also help them assess the need for booster doses to guard against emerging viral variants. The study “is an important step to further validate the use of the neutralization titer,” says Miles Davenport, an immunologist at the University of New South Wales in Sydney, Australia.

But the analysis has drawbacks. It is based on a small number of cases in young, healthy adults, limiting its application. It also does not suggest a particular level of antibody associated with protection.