Two months since Omicron emerged, where does Israel stand? Q&A with an expert
Did the travel ban help? Why aren’t vaccines working the same as with previous variants? Why don’t antibody counts tell us if we’re protected? Immunologist Dr. Yariv Wine answers
Nathan Jeffay is The Times of Israel's health and science correspondent
It’s been two months since the Omicron strain of coronavirus was identified. On November 24, South Africa reported the new variant to the World Health Organization, which quickly responded by designating it a variant of concern.
Within weeks, the highly infectious variant arrived in Israel. Today, the country is battling more coronavirus cases than at any point in the pandemic, and is leading the world in new daily COVID-19 cases per capita.
The variant has skyrocketed Israel’s total count of coronavirus cases since the start of the pandemic, taking it from 1.3 million at the start of December to 2.1 million today. Israel began December with 5,683 active cases; today that number is over 410,000. Some 0.6 percent of the population is testing positive per day, a world record.
So far those infection numbers aren’t translating into huge numbers of seriously ill patients — thankfully, Omicron is also far milder, in general, than previous strains — but doctors say it’s premature to relax.
Dr. Yariv Wine, Head of the Systems Immunology and Immunotechnology at Tel Aviv University’s Shmunis School of Biomedicine and Cancer Research, took stock of the situation in a Times of Israel interview.
Where does Israel stand today on COVID-19?
The guiding principle in Israel and many countries in the world is how to avoid overloading the health system. If it’s overloaded, there are many who aren’t coronavirus patients who are harmed, including cancer patients, emergency room patients and others… Maintaining the health system functionality will help to save lives not only of COVID-19 patients but all patients that need urgent health care.
So there is caution, but at the same time, policymakers are not making drastic decisions that disrupt life. They are able to do this because while there is an increase in the number [of people] with serious disease, it’s not in correlation to the people who are positive. And remember, the aim here is how to control the numbers and prevent the accumulation of people in hospitals.
Israel quickly stopped the entry of non-citizens when Omicron emerged and stayed shut until earlier this month when the variant was spreading fast in the community and imported cases from abroad were no longer the main worry. In retrospect, did this help?
Yes, it could well be that limitations on entry which reduced the arrival of Omicron cases slowed things down and helped us prepare for the wave. It gave us a window of time to better understand the variant.
The time between when it was identified and when it spread meant we knew much more about the variant, including its reduced aggressiveness and increased transmission. We were no longer in the dark. It gave the public time to prepare psychologically for the coming wave, and it gave hospitals time to prepare for fast-rising case numbers and put in place all they need to care for them.
Do we have an accurate sense of what level of antibodies, or of some other marker, protects from coronavirus infection?
No. For tetanus today we can say whether people need or don’t need a boost. If we knew the “correlate of protection” for Omicron, meaning a level of antibodies or other markers to know whether or not people are protected, we would be able to test people thus, facilitating decision making regarding whether a person needs to receive a boost. Discovering this takes time — and anyway what is true today won’t necessarily be true tomorrow. So we simply don’t have this at the moment for COVID-19.
Some teams are working on a “correlate of protection” for Omicron, and Sheba Medical Center claims to have some sense of what levels give protection, though it isn’t yet giving details. Will such antibody data mean we know exactly who is at risk of infection?
Not necessarily. Antibody levels can help in terms of protection, but there are other arms of the immune system that contribute to [protection], such as memory B-cells and T-cells. So you can have a person with relatively low antibodies but protection from the cellular memory arm will suffice. So it’s likely that people with high antibodies are protected, but we don’t know the levels, and some people may be below this and still have protection because of other cells.
Can you explain why vaccines are proving less effective against Omicron than among previous variants?
The immune response to the spike protein that is prompted by the vaccine generates two types of antibodies. There are those that bind to the spike protein and help clear the virus from the system, and [there are] neutralizing antibodies that actually block the ability of the virus to infect cells. The latter are the most desired antibodies.
The only vaccines in Israel are based on the spike protein, but the spike protein has changed with the Omicron variant. A percentage of the antibodies that are generated by the vaccine can still neutralize but it’s a smaller percentage than with previous variants. And it seems that when they do, it’s enough to reduce chances of hospitalization and serious disease, but in many cases not to prevent infection.
Vaccine companies including Pfizer were working on shots tailored to Omicron, and are expected to do the same for future variants. Should we be keen to use such vaccines?
It’s something we should consider and should be prepared to administer. And it could be possible to hold a reservoir of different vaccines tailored to different types of spike proteins, both mRNA vaccines and other types.
What do you expect to happen with Omicron, and are there any big questions regarding what this wave means for the future of the pandemic?
Omicron will eventually wane, I expect it to reduce relatively quickly as we see in some other places.
But there is no way to predict whether there will be another wave. And in my lab, we’re going to be looking into whether antibodies from Omicron will boost immunity against reinfection from Omicron and from other variants.
This is an important question as it gives an insight into what our level of immunity will be like after a wave that has infected so many people.
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