Ventilation better than deep-cleaning

People tend to think that science consists of absolute truths that will not change, forgetting that science is in fact self-correcting, using new facts and evidence coming out of research.

This has certainly been the case with COVID-19 and “fomite transmission,” or getting infected by fomites or objects that have come into contact with infectious substances, that we should be moving away from “deep-cleaning” to ventilation.

Remember in the early weeks of the pandemic when health authorities warned about “auto-infection,” saying that one had to be very careful when putting on a mask because if your fingers had come into contact with fomites—say, touching a table on which a COVID-infected person had coughed out droplets—you too could get infected if you accidentally touched your nose while putting on the mask.

Heaven knows how many of us were so fearful we couldn’t scratch an itchy nose, or anywhere on the face, imagining thousands of viruses crawling their way into our nasal passages and into our body.

You hardly ever see that “auto-infection” being used now.

But who can forget the news that the virus can survive for as long as three days on plastic? No wonder the Department of Education had people laboriously disinfecting plastic envelopes that were being used for teaching materials to be sent out to students.

Again, that was a waste of money and energy.

One of the research findings early in the pandemic found that the virus survived only for three hours on copper surfaces, with the result that entrepreneurs came out with copper-coated masks, supposedly for added protection.

Commercial interests profited immensely from all the scare around this fomite transmission, with the sales of all kinds of disinfectant chemicals, add on other measures like ultraviolet radiation. The problem was that all that research was conducted in laboratories, so very different from the real world, where the risks, it turns out, are almost zero, limited to environments involving prolonged exposure to a COVID-19 patient, in hospitals for example or at home with a patient.

The World Health Organization (WHO) tried to contain the panic, warning for example that fogging and misting with disinfectants were not recommended, and that if these were done using chemicals like chlorine, there was even the danger of poisoning those exposed.

But people wanted to believe they could do something to control the virus, and the fomite transmission angle allowed what has been called “hygiene theater,” which included an amazing range of measures that someday should go into museums of medical curiosities, from foot baths to the misting tents.

The United States’ Centers for Disease Control and Prevention (CDC) already toned down its warnings about fomite transmission last year but this new advisory in April 2021 is the most definitive yet.

It’s interesting that Europeans have been less paranoid about this fomite transmission that health authorities there hardly mentioned this “problem,” instead focusing on reminding people about masks, physical distancing, handwashing AND ventilation.

Ah, ventilation. The WHO also finally issued an advisory, “Roadmap to improve and ensure good indoor ventilation in the context of COVID-19” last March 1. The manual tends to get quite technical but its basic message is that we need to ensure good air flow in indoor environments, where nearly all COVID-19 infections take place.

Good air flow means fresh air must be able to enter the indoor environment while “old” air, which might contain aerosols from people with COVID-19, needs to be sent out. The more people entering a room and interacting for long periods—eating, conversing, having a meeting, doing karaoke—the greater the risks.

The Japanese have been warning about closed environments since March last year and against crowds, enclosed rooms, and close contact because of these aerosols, while prescribing masks, physical distancing, and good ventilation.

If you want to be somewhat sophisticated about measuring risks, you can buy fairly low-cost carbon dioxide meters, with electronic sensors that tell you what the level of carbon dioxide is in a room. In human respiratory cycles, we inhale oxygen and then exhale carbon dioxide. The carbon dioxide meter measures the amount of exhaled gases, with recommendations on risky levels.

Check the internet to download the CDC and WHO documents and, while you’re at it, look up indoor plants that are good at providing oxygen. Plants love the carbon dioxide we exhale, and give us oxygen in exchange, but some plants are better than others with oxygenating our environments, and people.

But again, don’t forget the basics: Masks, physical distancing, handwashing, and ventilation.

mtan@inquirer.com.ph