A study by Israel's largest health maintenance organization (HMO) Clalit Health Services has found that the UK Covid-19 variant causes a surge in more serious cases than the original virus.
Clalit Health Services examined 50,000 unvaccinated people who tested positive for Covid-19 during January and February, when the UK variant was the dominant virus strain in Israel. The researchers compared them with 60,000 unvaccinated people in Israel diagnosed with Covid-19 in previous waves, before the mutation first identified in Britain existed.
According to the data, prior to the UK Covid-19 variant, there was a 1% likelihood of people aged 30-50 becoming seriously ill, 3.7% for those aged 50-60 and 14.5% for those aged over 60. But in January and February in Israel when the UK variant was dominant, there was a 1.3% likelihood of people aged 30-50 becoming seriously ill, 5.5% for those aged 50-60 and 19% for those aged over 60.
Clalit said, "During January and February in the third lockdown and at the peak of Israel's vaccination rollout, we saw an inexplicable phenomenon. Forecasts predicted an immediate and major fall in the number of new seriously ill Covid patients each day. In practice, despite a high rate of people over 60 receiving their first vaccine dose, and subsequently even the second dose, the fall in the number of overall seriously ill patients was moderate."
It was during this period that the variant identified for the first time in Britain became dominant in Israel. This strain was seen in Israel for the first time at the end of December and by the start of February had already caused, according to Ministry of Health estimates, most of the infections in Israel. From several initial reports in England, it appeared that this variant might cause both more serious illness and substantially more deaths, although there was not data from Israel regarding this possible phenomenon."
Clalit Research Institute director Prof. Ran Balicer said, "Our data provides a possible explanation as to why in the first weeks of 2021, we did not see a sharp fall as expected in the number of new serious daily cases, despite the extent of the vaccination drive and the enormous efficacy of the vaccinations as seen in major research conducted by Clalit and published this morning in the New England Journal of Medicine."
He added, "According to the results we have, some of the overall fall in those of all ages who are seriously ill, following the vaccinations, was seen later and in a more limited way than expected, because of the sharp and simultaneous rise in serious infections, among those unvaccinated people in all age groups who were infected - a rise of 70% compared with the period one month previously.
"The results of the research tell us that since the start of 2021, the clinical characteristics of Covid morbidity have changed and the risk of serious Covid has increased significantly among the non-vaccinated population, and from here it is possible to assess that the British variant is not only more infectious but also more dangerous. These results match reports from Britain of the increased aggressiveness of the new strain."
Published by Globes, Israel business news - en.globes.co.il - on February 26, 2021
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