Science Unveils the Biggest Halloween Risks Due to COVID-19

Every holiday heralds fresh worries in 2020 due to the COVID-19 pandemic.

Quarantine concerns are used in the relaxed summer road ride. Family gatherings, especially if older relatives are involved, entail complicated risk-benefit considerations.

Halloween presents its problem this October. What should you do when trick-or-treaters show up at your house?

Good news: Amesh Adalja, a senior scholar at the Johns Hopkins University Center for Health Protection, says that trick-or-treating is not the most dangerous part of Halloween.

Instead, according to Robert Redfield, the head of the Centers for Disease Control and Prevention (CDC), limited indoor meetings controls the dreaded coronavirus surge.

"I think that those types of small gatherings where people haven't mixed before are going to be the challenge," Adalja told Inverse.

Halloween trick-or-treating, though, also carries a chance. There are two forms of risk: dissemination on the surface (doling to strangers out of candy) and people congregating on a doorstep.

(Photo: Rob Stothard/Getty Images)
LONDON, ENGLAND - OCTOBER 31: An installation of 3,000 candle-lit pumpkins blanket the canal side steps at Granary Square on October 31, 2014, in London, England. The pumpkins, created by members of the youth development group Global Generation and other carvers, will be on display and illuminated from dusk until Saturday, November 1, 2014.

Are you allowed to pass out candy? 

The chances of transmission of surface-based COVID-19 are far smaller than that of other directions in which the virus spreads. When someone speaks, coughs, sneezes, or sings, behaviors requiring repeated, non-masked, face-to-face encounters or detecting tiny aerosols are even more dangerous.

In the few instances where there might be fomite-based virus transmission (like within the household), there are so many other variables at stake that it is impossible to pin down transmission in that direction, a September review on transmission notes for Covid-19. Notably, CDC has not yet reported any event of Covid-19 resulting from food packaging.

But it's not to suggest that on soils, the virus can't live.

A widely read research in the New England Journal of Medicine has indicated that the virus lives on plastic and stainless steel for up to 72 hours but cardboard for fewer than 24 hours. More recently, a study reported in the journal Virology estimates that the virus may live on glass, stainless steel, or banknotes for as long as 28 days. COVID-19 may also last 14 days at the most on sticky surfaces such as cotton.

They come with a massive, substantial caveat, as bleak as these results are. In reality, the experiments do not imitate real life; they barely get close to the real-world environments in which we experience the coronavirus. For example, the latest experiment caused criticism because it measured the virus's survival in an area that was entirely dark (the virus is resistant to UV light) and at 64 degrees Fahrenheit and 50 percent humidity temperature climate-controlled.

The virus's capacity to survive on surfaces for some amount of time is just one explanation why that could be the case, says Montgomery. Virus molecules first have to land on a surface and get sick by hitting stuff, be experienced by another person until they are no longer viable, and eventually make it into the body.

For you and your sweets, here's how the science boils down. JoLynn Montgomery, the creator of risk-assessment company Epistudies and deputy assistant research scientist at the University of Michigan, told Inverse that no activity provides zero probability of transmission of Covid-19. Yet passing sweets out is at the low end of the danger scale, as long as it's in a package and no one has coughed or sneezed on it.

Studies say that the novel coronavirus can live under controlled laboratory conditions for up to 9 hours on the skin. The laboratory, again, is not the actual world. And handwashing decreases the danger significantly, says Adalja.

There are several situations where a surface faces a greater danger, such as where someone has coughed or sneezed explicitly on it lately. Yet dry, packaged candy isn't a problem in most situations.

That said, if you got exposed to COVID-19, skip the activities altogether.

Should you open your door?

Only one way a virus can transmit is a surface-based transmission. Early studies indicate that close social interaction with other people is a significant danger in Covid-19, and no touching is required. Instead, it could be enough to infect those around them by the aerosol droplets produced when a person speaks, sneezes, coughs, or sings. This is why social distancing and wearing masks are cited as effective techniques for infection prevention.

Montgomery claims this year she won't be opening her gates to trick-or-treaters. She is all too worried about cases of coronavirus circulating in her city.

"My county is in the low yellow range," she notes. "Right now, we have around 12 and a half incidents per 100,000 population, and that's more than I'm satisfied with," she says.

When considering whether to open your door to trick-or-treaters, you will even want to remember the positive test rate for your area.

The Johns Hopkins Coronavirus Information Center reports that 33 states in which the incidence of positivity of the coronavirus is greater than 5 percent, a number assumed to suggest a rise in cases and an indication of potential hospitalizations.

Adalja says that the danger remains low for the person doling out candy on the doorstep. That's because it's a "fleeting" interaction to hand out sugar, implying that it would not end in a substantial amount of publicity. Spending an extended period, perhaps 10-15 minutes or more, with another human within six feet and without masks is, nevertheless, a problem. So, cut short the talk.

"Nobody generally hangs around the door for sweets too long," Adalja says. "But for those who are extremely risk-averse, taking the candy out is the answer."

You will go farther to protect anyone, Montgomery notes, if you want to leave candy outside. The biggest threats derive from individuals assembling in groups and may arise on high-traffic trick-or-treating routes.

The alternative she suggests: don't force people to congregate around a candy bowl if you will leave out candy. By establishing a socially distanced candy scavenger hunt in the park, her neighbor brought this to a different stage, she notes. Spacing out candy bags at the end of a driveway would be another choice.

Scientists urged the public to be creative and do things differently for Halloween.

Check out more news and information on Halloween and COVID-19 in Science Times.