TOKYO – The new omicron variant of the coronavirus is spreading unchecked across the world. And recent research suggests that airborne omicron virus particles in aerosols may remain viable longer than their delta variant cousins - the version that fueled the fifth wave of infection in Japan – thanks to a kind improved protective coating, potentially increasing its transmissibility.
It is now well known that the coronavirus is spread when a person breathes viral particles in tiny droplets – aerosols – expelled when an infected person exhales or coughs. The same mechanism is at work with other airborne pathogens like tuberculosis and measles, and all of them could be called “aerosol infections”.
There have been several reports of transmission of omicron by such aerosols. In a Hong Kong hotel, a person was infected by another guest staying in a room across the hall. In another case, 61 of some 600 passengers on flights between South Africa and the Netherlands were found to be carriers of COVID-19, including 13 with omicron.
“The previous variants are also spread by aerosols,” noted Nobuaki Shimizu, professor and infection control expert at Aichi Prefectural University in Nagakute, Aichi Prefecture. “In places like on the Diamond Princess (cruise ship) and in hospitals, the stale air containing the virus has been recycled repeatedly, so there have been a lot of cluster infections even among people staying in. different rooms. There must be an investigation into exactly what’s going on with the ventilation in this Hong Kong hotel and on the airplanes, but it is certain that there are omicron aerosol infections. ”
But how does omicron spread through the air? A research team from the University of California created an aerosol containing the coronavirus and, using the Summit supercomputer at the Oak Ridge National Laboratory in Tennessee, simulated the mechanics of an aerosol spread. According to the team’s findings, which have yet to be peer-reviewed, it appears that substances called mucins – proteins from the lining of the lungs – in human aerosols attract the peak proteins dotted with the coronavirus. The reason is simple in physics: the mucins are negatively charged and the spike proteins have a positive charge, so the mucins seem to congregate around the viral particles.
According to a New York Times report on the research, the team believe the mucins that bind to advanced proteins form a protective coating, preventing damage to the virus. And the omicron variant acquires a more effective coating than the delta variant, which means it could remain infectious longer outside the body.
The total number of coronavirus infections remains low in Japan. But the dry air that accompanies the onset of winter makes it easier to catch aerosol-borne infections, and it is believed that increasing social activity towards the end of the year will increase the chances of transmission.
Professor Shimizu pointed out that previous variants such as alpha and delta started to spread inside the country at times like now, when global infections were at a low ebb. Also in South Africa, the number of omicron cases started to increase when the delta variant was brought under control. “It is easier for the newer variants to spread when the old ones are in decline because that means the newer version has less competition,” Shimizu said.
Asked what measures Japan should take to counter the potential spread of omicron nationally, Shimizu stressed that “urethane foam masks have almost no anti-infective effect.” He added: “Making sure there is no space (between your mask and your face), such as wearing two nonwoven fabric masks, is effective, as is making sure to maintain a good fit. ventilation.”
On how the virus is transmitted, the Department of Health, Labor and Welfare had previously only mentioned fluid sprays and close contact. However, in October 2021, the ministry updated the information on its website to recognize aerosol infections. He also changed the information on the route of transmission in his diagnostic and treatment advice to doctors, from “spray and close contact” to “spray and aerosol”.
(Japanese original by Naomi Hayashi, Lifestyle and Medical News Department)