As of today 719,037, of our friends and neighbors have died from SARS-CoV-2 (COVID-19). However, perhaps, at least in the foodborne illness space, there might be some good news?
The CDC reported today on the Decreased Incidence of Infections Caused by Pathogens Transmitted Commonly Through Food During the COVID-19 Pandemic — Foodborne Diseases Active Surveillance Network, 10 U.S. Sites, 2017–2020.
According to the CDC, there has been a 26% decrease in incidence of infections caused by pathogens transmitted commonly through food during 2020 which was the largest single-year variation in incidence during 25 years of FoodNet surveillance.
The questions posed by the CDC in part were answered and in part not.
1. Did widespread public health interventions implemented to prevent SARS-CoV-2 transmission might have contributed to this decrease? For example, infections associated with international travel decreased markedly after pandemic-related travel restrictions were imposed. Other interventions, such as restaurant closures, might have contributed to declines in incidence.
2. However, a higher than usual proportion of infections might have been undetected because factors such as changes in health care-seeking behaviors, and broader use of telehealth might have limited the number of stool specimens tested.
3. Marked decreases in emergency department visits for abdominal pain and other digestive or abdominal signs and symptoms occurred early in the pandemic which would have decreased reports of foodborne illnesses.
4. Of concern was the proportion of infections resulting in hospitalization increased slightly; possible explanations include disproportionate decreases in health care-seeking among those with milder illness or delayed health care-seeking resulting in more severe illness at the time of clinical presentation.
5. Changes in clinical and public health laboratory capacity in response to the COVID-19 pandemic might have contributed to observed decreases in culturing. Before 2020, culture of specimens positive for Campylobacter, Salmonella, Shigella, and Yersinia increased in FoodNet sites, augmented by CDC funding. However, fewer cultures decrease the ability to detect and investigate outbreaks and sporadic cases of emerging pathogens, which relies on sequencing.
6. The incidences of Salmonella Infantis, Cyclospora, and Yersinia infections, which had previously been increasing, did not change, possibly because of continuing prepandemic factors that led to rising incidences during previous years; the stable incidences despite the pandemic suggest that they might have increased otherwise.
7. As pandemic-related restrictions are lifted, illnesses caused by these pathogens and by Hadar, the one Salmonella serotype with increasing incidence, should be closely monitored. Rising multidrug resistant Salmonella Infantis infections have been linked to consumption of chicken. Hadar infections have been linked to backyard flocks and to consumption of turkey. USDA-FSIS did not detect a significantly higher percentage of Salmonella Hadar in raw poultry samples collected in 2020 compared with 2017–2019. Typhimurium continued to decline in rank among Salmonella serotypes, dropping to fourth most common for the first time.
The CDC noted that the findings in this report are subject to at least three limitations. First, the pandemic and corresponding public health response make explaining changes in the observed incidences of infections challenging. Second, changes in health care-seeking behaviors and health care delivery during the pandemic likely limited ascertainment of cases. Finally, sites reported decreases that varied over time in the willingness of ill persons to be interviewed and in staff member capacity to conduct case interviews; these factors might have resulted in missing data and recall bias.