A much milder form of disease among vaccinated COVID patients early in the omicron wave is indisputable, Israeli experts are saying as the new variant is spreading uncontrollably across the country.
Overall in Israel, according to Health Ministry data, only 14 percent of Israelis over 20 are unvaccinated, yet they account for 45 percent of serious COVID cases. The numbers are even more clear when examining the use of life-saving measures such as ECMO machines and ventilators.
“Right now there are 13 very severe cases in which the patients are on ECMO machines – 100 percent of those patients are not vaccinated,” added Prof. Nadav Davidovitch, a health policy specialist at Ben-Gurion University, referring to the machines that support the heart and lungs in the worst respiratory cases.
“We also see that 81 percent of patients in the hospital on ventilators are either not vaccinated at all or only partially vaccinated. And among our 57 severely ill patients who are younger than 60 years old, 43 are unvaccinated.”
The differences are even more stark when examined based on patients' age groups. Among Israelis between the ages 60-69, there are 40 severe cases per 100,000 people among the unvaccinated, but only 2.8 severe cases per 100,000 people among the vaccinated. Among those aged 70-79, the ratio is 46.6 severe cases per 100,000 people among unvaccinated, versus 6.8 among the vaccinated.
These statistics have slowed Israel’s march toward offering a fourth vaccine dose to people under 60, said Prof. Hagai Levine, chairman of the Israeli Association of Public Health Physicians.
“What we are seeing is that the risk of severe disease among people who received three doses of vaccine and are under the age of 60 is extremely low,” Levine said. “That’s putting a question mark on the need for the fourth dose for people under 60.”
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The correlation in Israel between disease severity and vaccination status seems to be following the pattern of the United States, where omicron hit full force several weeks earlier, according to Dr. Oren Kobiler, a researcher in immunology and clinical microbiology at Tel Aviv University. In New York, almost 90 percent of COVID hospitalizations are of unvaccinated people, Kobiler notes.
“While we can see that more vaccinated people are getting infected in this wave than in the past, they are affected much less severely than the unvaccinated,” he said. “This is what we were hoping for in terms of offering evidence that vaccinations work.”
Kobiler has a theory on countries where there is less of a correlation between vaccination and severity of disease during the omicron wave.
“There are some places where many of those counted as unvaccinated include many people who previously recovered from infection,” he said. “Both South Africa and the United Kingdom, for example, encountered huge COVID waves earlier in the pandemic during which they weren’t able to keep up when it came to recording who got infected.”
These people may be listed as unvaccinated when they have actually recovered, and thus possess antibodies similar to those resulting from a vaccine.
“That somehow contaminated the data, because recovered people are like the vaccinated in many ways – you don’t see a lot of purely unvaccinated people in these countries,” Kobiler said.
In Britain when omicron began, the percentage of people who were both unvaccinated and not recovered from COVID is estimated to be as low as 5 percent, Kobiler said – compared with 20 to 30 percent in the United States.
“These are the people we really need to watch for the onset of severe disease and learn from them. We’re seeing that omicron behaves differently – it seems to be less pathogenic to the lungs and there is less need for oxygen and ventilation,” he said.
“Still, the number of severely ill patients is rising, and most of them have the omicron variant – we still don’t have clear data. But we definitely see that the most severe omicron infections happen when people are unvaccinated or have a defective immune system that renders the vaccine ineffective.”
In Israel, Kobiler warns, it is far too early to say the hospitals are not in danger of another inundation of severe COVID cases.
“The massive numbers have just begun in the last few days, and it takes a week before disease turns severe. Also, in Israel the waves have started with people coming from abroad bringing in a variant like delta or omicron, and the travelers come from higher socioeconomic backgrounds. These are the people who are more likely to be vaccinated, along with the people they come into contact with,” he said.
“For that reason, what we have seen before with delta and will likely see in the omicron is that at the beginning of the wave there are wealthier and more-vaccinated people getting infected. Only later do we see people from the lower socioeconomic levels who are unvaccinated, and that’s when we may begin seeing the problems in the hospitals.”
Levine says the far higher risk of severe illness in this wave crosses all age groups, so “we still need to push those who didn’t get vaccinated to get vaccinated as much as possible. The vaccine provides good protection against severe disease across age groups, and our unvaccinated population is still at risk for a severe case – even during omicron.”
Experts say Israel is seeing a slow increase in the vaccination rate among children under 12, as with people getting their third or fourth doses.
While the current low death rate may stem from omicron’s more mild nature, Levine notes that most of Israel’s vulnerable population is fully vaccinated.
“The current risk for mortality is definitely lower than it was in the past when the population was not vaccinated and the dominant variant was more virulent,” he said.