A surveillance survey published in Virus Research finds an almost 70% elevated prevalence of SARS-CoV-2 antibodies in the blood of pet dogs exposed to the virus in their homes. 

Researchers from the University of Pittsburgh and Zoetis, developer of the SARS-CoV-2 lateral-flow assay (LFA) used in the study, analyzed serum samples from 196 dogs in Pennsylvania for viral antibodies from November 2021 to March 2022. 

The dogs included those that were exposed to COVID-positive human household members, had recently had a SARS-CoV-2 infection, or had no exposure. The animals showed no signs of SARS-CoV-2 infection and were brought to the vet clinic for other indications.

"Human to animal [SARS-CoV] spillovers have been documented both in domestic and wild animal species," the study authors noted. "Due to close contact in shared households, pet dogs may be at increased risk for contracting the SARS-CoV-2 virus from infected individuals in the same household." 

Importance of continued surveillance

Dogs exposed to COVID-positive household members had a significantly higher SARS-CoV-2 seroprevalence (68%) than other dogs. Seroprevalence among all dogs, determined using a surrogate virus neutralization test (sVNT), was 12.2%.

These findings provide serological evidence of SARS-CoV-2 spillover to pet dogs and underscore the importance of continued surveillance in companion animals.

All sVNT-positive sera were also positive on a pseudovirus neutralization test (pVNT) except for samples from one dog, likely due to a weak antibody response. Antibody levels, determined using a panel of spike pseudoviruses in the pVNT test, revealed higher concentrations against the Delta, Gamma, and Alpha variants than against Omicron. 

The sensitivity and specificity of the LFA was 85% compared with the sVNT and 75% compared with the pVNT, indicating its potential for field use in dogs, the authors said.

"These findings provide serological evidence of SARS-CoV-2 spillover to pet dogs and underscore the importance of continued surveillance in companion animals as part of a One Health approach, especially as new viral variants continue to emerge," they wrote.

Yesterday Pfizer and BioNTech reported phase 3 clinical trial data for their updated COVID vaccine, Comirnaty. That vaccine is authorized for use by the Food and Drug Administration (FDA) for seniors 65 and older and for younger adults with at least one underlying health condition.

The data show at least a fourfold increase in neutralizing antibodies, reinforcing preclinical data, and Pfizer has submitted these data to the FDA.

4-fold increase in neutralizing antibodies 

The trial included 50 adults ages 65 and older and 50 adults ages 18 to 64 with at least one underlying health condition. All received the LP.8.1-adapted COVID-19 vaccine 2025-26 formula, and had previously received the KP.2-adapted COVID-19 vaccine at least 6 months prior to enrollment.

The safety profile of the vaccine was consistent with previous studies, with no new safety concerns identified.

"In both age groups, 14 days following vaccination, LP.8.1-neutralizing antibody titers exceeded pre-vaccination levels, on average, by at least 4-fold," Pfizer said in a press release. "The safety profile of the vaccine was consistent with previous studies, with no new safety concerns identified."

Pfizer said this information was given to the FDA to provide additional information about immunological effects of the vaccine, and is not intended to replace the post marketing commitments requested by the FDA.

Correction: This article has been updated to reflect that two dogs tested positive for OPXV antibodies. The original version misstated the number of dogs and for what they tested positive.

A Centers for Disease Control and Prevention–led study links spillover from small mammals such as voles and squirrels to cases of borealpox in five adults and one child in Alaska from 2020 to 2023.

Borealpox virus (BRPV; formerly Alaskapox virus) is an orthopoxvirus (OPXV) first found in 2015 in a woman living near Fairbanks, in Alaska's interior. The infection was identified as a novel OPXV, but the source was unidentified.

Published yesterday in Clinical Infectious Diseases, the study involved patient or parent interviews, trapping 176 wild small mammals at six sites for OPXV testing, and phylogenetic analyses of viral DNA sequences to reconstruct their evolution.

Nearly all OPXVs are zoonotic viruses that infect mammals, with rodents often the primary animal reservoir. "Human population immunity to OPXVs is waning globally after the eradication of smallpox, which is likely a reason why OPXVs are being identified with increasing frequency globally," the investigators wrote.

Immune-compromised patient died

Five of the infected patients had one or more lesions and lymph node swelling and later recovered, most after receiving antibiotics. The other patient, an older man with a weakened immune system, was hospitalized and died despite receiving experimental OPXV medications. 

Better understanding BRPV ecology might help develop more focused prevention measures in addition to standard recommendations to prevent zoonotic infections, such as practicing hand hygiene and avoiding contact with wild animals.

One patient reported vaccination against smallpox, and all had contact with domestic animals, many of which hunted small mammals. Two patients' dogs tested positive for OPXV antibodies in the blood, but the authors noted that it is unclear if the dogs were recently infected with BRPV.

No patients had traveled outside of Alaska, and no evidence of person-to-person spread was found. All BRPV genomes were nearly 100% identical to that of the virus isolated from the 2015 patient.

Several small-mammal species had BRPV DNA and evidence of past OPXV infection in their blood. Genetic distance and phylogenetic analyses pointed to multiple animal-to-human spillover events.

"Better understanding BRPV ecology might help develop more focused prevention measures in addition to standard recommendations to prevent zoonotic infections, such as practicing hand hygiene and avoiding contact with wild animals, including taking measures to keep small mammals out of buildings," the authors wrote.

They called for research into BRPV's geographic range in small mammals in northern regions.

The Cystic Fibrosis (CF) Foundation announced today that it is investing $7.6 million in Danish microbiome technology company SNIPR Biome to develop a cocktail of engineered bacteriophages targeting a common cause of chronic lung infections in CF patients.

The phage therapy developed by SNIPR Biome will be designed to eliminate persistent Pseudomonas aeruginosa infections, which can cause significant lung damage in CF patients, are often multidrug-resistant and difficult to eliminate, and require long-term use of inhaled antibiotics. Because of the mucus that builds up in their lungs, CF patients are prone to bacterial infections that can exacerbate their condition. 

Identifying optimal phages

To develop the cocktail, SNIPR plans to collect phages—live, naturally derived viruses that target and kill specific bacteria—from people with CF and other lung diseases and screen for phages that are active in conditions that emulate the CF lung. The company will then use CRISPR-Cas gene editing technology to improve the ability of the selected phages to infect and kill P aeruginosa.

The funding will help SNIPR develop and identify the best engineered phages for P aeruginosa infections and advance them into clinical trials.

"Engineered phages seek to build upon successes already observed with naturally derived phages and may be the next evolution in understanding the full potential for phage therapy in cystic fibrosis or similar airway diseases," Dave Nichols, MD, senior director of clinical research development at the Cystic Fibrosis Foundation, said in a press release. "Our investment could help us better understand whether SNIPR's approach can effectively overcome certain challenges when trying to eliminate chronic airway infections."

Officials have confirmed four more H9N2 avian flu cases involving boys from different provinces on mainland China, the Hong Kong Centre for Health Protection (CHP) said today. The patients had illness onsets in late July and August.

According to the CHP, the patients include a 1-year-old, two 2-year-olds, and a 6-year-old, and all patients are male. Mainland China has now reported 19 H9N2 cases in the past 6 months. At least 13 of the cases have been in young children. 

In 2024, the country reported 11 total H9N2 cases.

H9N2 avian flu is known to circulate in poultry in China and other parts of Asia, and sporadic human infections have been reported, mainly in China. Infections are typically reported in children, who usually experience mild infections. Some infections, however, are severe.