Concerns regarding risk factors for SARS-CoV-2 transmission to pets

I read with interest the paper by Alberto-Orlando et al [1] entitled “SARS-CoV-2 transmission from infected owner to household dogs and cats is associated with food sharing”. Investigation of human-animal transmission and factors associated with that is an important area of study. The authors report interesting prevalence data, but also an association between food sharing and SARS-CoV-2 infection in pets. That risk factor would be biologically plausible; however, the data and analysis are unclear and do not appear to support that conclusion.

Description of the analysis is very superficial and provides little information about the methods. For multivariable analysis, the authors report a significant association between food sharing and infection (P = 0.0025) with an odds ratio of 6.17. Yet, the reported 95% confidence interval (0.22-167.4) is very broad and is inconsistent with a statistically significant result. The bivariate analysis for this variable yielded a P-value of 0.61, and it is surprising that such a change could result from multivariable analysis, especially with such a small sample size and a limited number of variables. This raises the question of whether there was an analysis error as it is very difficult to see how a significant result such as this could be obtained.

Declaration of competing interest

The author has no competing interests to declare.