COVID-19 sniffer dog experimental training: Which protocol and which implications for reliable sidentification?

J Med Virol. 2021 Oct;93(10):5924-5930. doi: 10.1002/jmv.27147. Epub 2021 Jun 26.


The introduction of trained sniffer dogs for COVID-19 detection could be an opportunity, as previously described for other diseases. Dogs could be trained to detect volatile organic compounds (VOCs), the whiff of COVID-19. Dogs involved in the study were three, one male and two females from different breeds, Black German Shepherd, German Shepherd, and Dutch Shepherd. The training was performed using sweat samples from SARS-CoV2 positive patients and from SARS-Cov2 free patients admitted at the University Hospital Campus Bio-medico of Rome. Gauze with sweat was collected in a glass jar with a metal top and put in metal boxes used for dog training. The dog training protocol was performed in two phases: the olfactory conditioning and the olfactory discrimination research. The training planning was focused on the switch moment for the sniffer dog, the moment when the dog was able to identify VOCs specific for COVID-19. At this time, the dog was able to identify VOCs specific for COVID-19 with significant reliability, in terms of the number of correct versus incorrect (p < 0.0001) reporting. In conclusion, this protocol could provide a useful tool for sniffer dogs' training and their introduction in a mass screening context. It could be cheaper and faster than a conventional testing method.

Keywords: COVID-19; VOCs; dog training; sniffer dog.

MeSH terms

  • Animals
  • COVID-19 / diagnosis*
  • COVID-19 / pathology
  • Dogs
  • Female
  • Humans
  • Learning / physiology*
  • Male
  • Middle Aged
  • Reproducibility of Results
  • SARS-CoV-2 / isolation & purification
  • Smell / physiology*
  • Sweat / chemistry
  • Volatile Organic Compounds / analysis
  • Volatile Organic Compounds / isolation & purification
  • Working Dogs / physiology*


  • Volatile Organic Compounds