Japanese scientists found that the omicron strain of Covid-19 is at least 40% more deadly than seasonal flu, underscoring the danger of lifting pandemic curbs too quickly and underestimating the virus’s ongoing health risks.
A recent analysis by scientists who advise Japan’s health ministry estimated the case-fatality rate for omicron at about 0.13%, based on excess deaths and infections since January. They said it is lower than the 4.25% case fatality rate seen earlier in the outbreak, but it is still higher than the 0.006% to 0.09% seen with seasonal flu.
Around the world, mitigation measures have been loosened, from mask mandates to testing requirements, and countries are pushing for a return to normalcy. The public has become tired of restrictions, and the reduced severity Omicron has reassured many that the rules are no longer necessary. Although Japan has not formally downgraded its condition, it is easing border restrictions and quarantine periods for travelers, essential workers, and close relatives of positive cases to keep the economy going.
The decline in mortality with Omicron could be due both to the reduced virulence of the strain, particularly compared to the delta variant, and to the benefits of vaccination, according to the researcher. Their findings demonstrate the importance of putting control measures in place before vaccines are widely distributed.
To determine the impact of the easing once the restrictions are lifted, more study is needed, Takaji Wakita, chair of the health ministry’s advisory board, said at a briefing Wednesday night. As of this date, most of the pandemic curbs were still in place, he explained.
The study, which hasn’t been peer-reviewed or published in a medical journal, is subject to several limitations, including differences in data collection that make cross-comparisons difficult, says Wakita.
However, there is still a considerable difference in mortality between Covid and influenza, despite the arrival of omicron, he said.
As a result of the omicron-fueled wave, some Omicrons in Japan have sought quasi-emergency states that restrict the operation of bars and restaurants. There are currently measures in place in 31 of the country’s 47 prefectures until March 6. NHK reported Wednesday that some areas, such as Osaka and Kyoto, have asked to extend them, while others have asked for them to be lifted.