COVID-19: An owner who tests positive significantly increases the likelihood of their dog becoming seropositive

Since 2020, it has been recognized that dogs can become infected through contact with an owner who tests positive for SARS-CoV-2. A study published in *Virus Research* supports this finding with serological data and confirms that close contact is a risk factor for infection.  

196 dogs, 4 months, 2 tests

Conducted in Pennsylvania between November 2021 and March 2022, the study included 196 dogs seen in veterinary clinics for various reasons. The authors used a SARS-CoV-2 surrogate virus neutralization test (sVNT) to measure seroprevalence and determine the nature of the neutralizing antibodies, as well as a rapid screening test (lateral flow assay). None of the dogs showed clinical signs attributable to COVID-19 at the time of sampling, placing the results in the context of infections that are most often subclinical.  

Increased Risk in Case of Contact with a Positive Case

Across the entire tested population, seroprevalence reached 12.2%. Among dogs that had lived with at least one positive human, it rose to nearly 68%, indicating a significant increased risk associated with close exposure. Neutralizing antibody titers were found to be higher against the Delta, Gamma, and Alpha variants than against Omicron, consistent with Omicron’s immune escape profile already documented in humans.  

Rapid Test vs. Laboratory Test

The lateral flow assay (LFA) has a sensitivity of approximately 85% compared to the neutralization test (sVNT). In practice, it can serve as an initial screening test, particularly in general veterinary practice or in field studies. For decisions with high scientific or veterinary public health stakes, the neutralization test (sVNT) remains the methodological gold standard, as it provides a more reliable measure of antibody activity. The results support the hypothesis of human-to-dog transmission within the household. The study demonstrates neither dog-to-human transmission nor a marked clinical impact in the dogs in this sample, but it fully justifies including pets in “One Health” surveillance systems to monitor the emergence of variants and clarify the interspecies risk.  

Guidelines for Home and Veterinary Settings

In a household where a person has tested positive for COVID-19, limiting close contact with the dog and practicing good hand hygiene are common-sense measures. In veterinary settings, an LFA test can quickly guide management, reserving the sVNT test for situations requiring greater scientific precision, whether for epidemiological surveillance, research, or investigation of a cluster.   Living with a person who has tested positive for COVID-19 significantly increases the likelihood of anti-SARS-CoV-2 antibodies in dogs. The lateral flow assay allows for rapid diagnosis, but the neutralization test remains the scientific gold standard.