Researchers at Kyoto Prefectural University of Medicine in Japan compared the survivability on surfaces of the original coronavirus — found in Wuhan, China in late 2019 — and the worrying variants Alpha, Beta, Gamma, Delta and Omicron. In a study not yet peer-reviewed, scientists concluded that Ômicron is the most resistant in the external environment, staying up to 21 hours on the skin and up to 193 hours (the equivalent of eight days) on plastic surfaces.
Despite the enormous capacity for contagion of Ômicron, the director-general of the WHO made an optimistic prognosis today, but left a warning. For Tedros Adhanom Ghebreyesus, “we can end the acute phase of the pandemic this year and end Covid-19 as a global health emergency”, which is the highest alert level of the WHO.
However, Adhanom warned that it is “dangerous to assume that Omicron will be the last variant and that we are at the end of the game”, because conditions are “ideal” for other variants to emerge, including more transmissible and virulent ones.
The Japanese study of Omicron on skin and surfaces was unable to conclude to what point the virus was still able to infect people while it remained alive on the surface.
The viral samples used in the study were provided by the National Institute of Infectious Diseases in Tokyo. The researchers tested survivability on a polystyrene (plastic) plate and on human skin (human skin samples collected for forensic autopsy were used).
Scientists found that Omicron is the most resistant on the plastic surface (193.5 hours), followed by Alpha (191.3 hours), Beta (156.6 hours), Delta (114 hours), Gamma (59.3 hours). hours), with the strain originating in Wuhan being the one that survived the least, staying 56 hours.
The time spent on human skin was lower compared to the plastic surface, with Ômicron being the most resistant (21.1 hours), followed by Alpha (19.6 hours), Beta (19.1 hours), Delta (16 hours). .8 hours), Gama (11 hours) and from Wuhan (8.6 hours).
This increased survivability of Omicron, the study authors suggest, could explain why the new variant quickly replaced Delta.
“In theory, if these particles found on surfaces are contaminants, then this could explain part of the Ômicron infection process. The work raises a question to be answered and they say the best research is the one that leaves open questions to be answered”, says physician Salmo Raskin, geneticist and medical director of the Genetika Laboratory in Curitiba.
The researchers also tested the effectiveness of disinfectants based on alcohol, ethanol and isopropanol against the coronavirus. They noted that all were effective against the virus. However, the concern variants were slightly more resistant than the original strain.
On human skin, the evaluation showed complete inactivation of all viruses with exposure to 35% ethanol within 15 seconds. Therefore, the researchers strongly recommend that the current protocol of hand hygiene practices continue for infection control as recommended by the World Health Organization.