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What scientists want us to know about the invisible enemy in the car cabin

The ongoing COVID-19 pandemic has effected a two-pronged attack on us humans: The physical and the psychological. The physical one is obvious—you get the virus, you go down with the disease and its symptoms (in varying degrees). The psychological one is a bit subtler but no less immobilizing—the fear and paranoia that grows on us, no doubt resulting from swinging and punching at an enemy we can’t see, and therefore, we feel helpless against.
This dual attack is probably most evident when we share breathing space with fellow humans in confined quarters, such as in the cabin of motor vehicles. What happens in that square meter of air between you and your fellow passenger? What deadly entities may hitch a ride on your fingers when you touch the door handles, knobs, buttons, and the locks that he or she has also touched? You may not have contracted the virus, but your mind is already infected with fear.
Knowing how viruses (especially the novel Coronavirus) behave inside confined quarters, and then applying scientific measures to counter these behaviors, may help ease your mind when you’re out on a drive with someone else in the car. It’s like “mind vaccination”. When you know you’ve done what’s necessary to minimize your risk of getting sick, irrational fear is kept at bay. You’ve already won half of the war, and you can better focus on the task at hand, which is keeping your eye and your mind on the road.
For this end, we’ve picked the brains of experts in microbiology, virology, and molecular medicine, and share with you their expert opinion on bacteria and viruses.

Dr. Leodevico Ilag


Dr. Leodevico L. Ilag, a DOST “Balik Scientist” (meaning, a scientist who was once based overseas and is now residing and practicing his or her field of expertise in the country), has a PhD in Microbiology and Immunology, and is a Postdoctoral Research Fellow in the structural biology of viruses and viral proteins. He tells us, in a nutshell, how some bacteria and viruses behave inside a vehicle: “In general, respiratory viruses and bacteria (such as tuberculosis-causing Mycobacterium) are dispersed as aerosol and can remain in the air inside the car, increasing the chance of transmission. However, most bacteria will most likely be present on surfaces in the car.”
Dr. John Carlo M. Malabad, MD, PhD in Molecular Medicine, and an Assistant Scientist of the Philippine Council for Health Research and Development Department of Science and Technology, adds, “Bacteria and viruses behave similarly in closely confined environments, as with open-air environments. However, the risk of spread of bacteria and viruses increases significantly in closely confined environments because of the limitation in air flow.”
So, knowing that viruses and bacteria do have the ability to travel via air, what can we do to minimize getting infected by fellow passengers? A number of sprays and liquid disinfectant products have come out claiming to eliminate deadly bacteria and viruses.

Dr. John Carlo Malabad


Efficacy of sprays and disinfectants
Ilag is of the opinion that, overall, such claims are true. But the efficacy of these sprays and disinfectants depends on the type of bacteria and viruses they are intended to be used on.
“In general, the ingredients need to be in the right concentration and contact time. The more effective ones are povidone-iodine (as low as 0.5%). Ethanol/isopropyl alcohol needs to be 70 percent to be potent,” Ilag discloses.
Fellow Balik Scientist Dr. Elpidio Cesar Nadala Jr, who has a PhD in Microbiology and Animal Virology and post doctorate in Aquatic Virology and Medical Biotechnology, confirms that “Ethyl and isopropyl alcohol at 60 to 90-percent concentration are very effective against bacteria and viruses, except for poliovirus and hepatitis A virus, which require clorox (10 percent commercial bleach) for inactivation.”

Dr. Elpidio Cesar Nadala Jr.


Another Balik Scientist, Dr. Lourdes Nadala, who has a PhD in Microbiology (Major in Animal Virology) stresses: “Most disinfectants do not claim a 100-percent kill. Therefore, if the viral or bacterial load is high, there will be some left, hence, we are advised to keep on washing our hands as often as possible to reduce the risk of infection.”
Ilag says 70-percent ethanol/isopropanol and coconut oil would be effective hand sanitizers.

Dr. Lourdes Nadala


How long does the Coronavirus, particularly the more contagious Delta variant, linger in the air of the car cabin or on the vehicle’s interior surfaces?
Ilag opines, “It’s possible that the Delta variant stays longer in the air and surface compared to the original viral strain since it may be one of the traits Delta was selected for in addition to its ability to make more virions (complete copies of itself). These traits can explain the high transmissibility of the virus”.
Dr. Elpidio Cesar Nadala Jr. estimates: “Based on aerosol studies, the approximate time is 8 to 14 minutes. In laboratory-controlled studies at high concentration of virus, it can last up to six days on plastic and metal surfaces. In real world conditions, up to 15 minutes on surfaces.”
Malabad says: “Disinfectants are generally able to eliminate almost all microbes or germs on surfaces and inanimate objects. Disinfectants are chemicals (such as soap, detergent, alcohol, quaternary ammonium, hydrogen peroxide, sodium hypochlorite/bleach) that destroy the cells or outer layers of microbes, thereby killing or inactivating them.
“But we have to remember that there are certain factors affecting the effectiveness of disinfectants. They need to have the right concentration and sufficient contact time in order to kill bacteria and viruses. For example, a disinfectant with at least 60 percent alcohol is effective against SARS-COV-2, the virus that causes Covid-19, but any concentration less than that is less effective. Another is that some of the mentioned ingredients which are effective against viruses and bacteria such as quaternary ammonium, hydrogen peroxide, and sodium hypochlorite are abrasive and could damage vehicle upholstery and interior surfaces, so checking the material to which you will apply the disinfectants would also be prudent,” said Malabad.

Dr. Ruby Anne Natividad King


Dr. Ruby Anne Natividad King, MD, PhD and an Assistant Scientist of the PCHRD, says: “According to the World Health Organization and published studies, viable SARS-COV-2 particles can remain on surfaces or suspended in the air for several hours to days, depending on environmental factors like temperature and humidity and the type of surface.”
King’s advice would be “to avoid or minimize exposure, entailing the practice of proper handwashing and other minimum public health standards (wearing personal protective equipment, physical distancing, coughing/sneezing hygiene, avoidance of touching surfaces then touching eyes, nose, mouth). Specifically, for viruses for which vaccines have been developed and approved, vaccination is highly recommended to protect oneself from infection.”

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