I chose not to hand out candy this Halloween. The covid numbers in my area have been steadily increasing and I just didn’t want to take the risk of contributing. But what are the risks of transmission through Halloween candy?
It seems that the science is fairly certain at the moment that most transmission of SARS-CoV-2, the virus responsible for covid-19, happens through respiratory droplets and aerosols (hence the mask wearing). However, transmission via fomites, objects that may have been contaminated, is still possible. Halloween candy has the potential to act as fomites, transmitting covid between people. Salido et al (2020) tested whether or not they could detect the virus on Halloween candy that had been handled by individuals who were recently diagnosed as asymptomatic or mildly/moderately symptomatic with covid-19.
The study examined two mitigation methods, hand-washing by the infected individual prior to handling the candy and washing the wrapped candy with dishwashing detergent. The results were pretty good. Sixty percent of candies that had been handled by the covid-19 infected individuals without handwashing had the virus on it, but only 10% of the candies were potential fomites if the individual washed their hands properly before handling the candy. In addition with a minute or more of washing with dish detergent the virus load was reduced by more than 60%. This meant that the viral load was reduced to near zero when handwashing and candy washing were combined.
This hopefully means that we won’t see huge spikes following this weekend’s events but it does depend on the behaviours of people. Having become increasingly aware of how often I do things like touch my face, I’m not sure that I have confidence that over the course of the evening I would have remembered to wash my hands before handing out candy every single time. And, I’m not sure how many people would be washing their candy when they got it home.
Still, as we don’t know how long this pandemic or the risk of covid will continue for, it is good to know that there are mitigation strategies that we can use to help keep each other safe.