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New Omicron-busting shots score a point in race against variants – expert

Vaccines will increase protection even though Omicron has already changed since they were developed, says Bar-Ilan epidemiologist

Nathan Jeffay

Nathan Jeffay is The Times of Israel's health and science correspondent

Illustrative image: A health worker prepares a Pfizer COVID-19 vaccine at a vaccination clinic in Chester, Pennsylvania, on Dec. 15, 2021.  (AP Photo/Matt Rourke, File)
Illustrative image: A health worker prepares a Pfizer COVID-19 vaccine at a vaccination clinic in Chester, Pennsylvania, on Dec. 15, 2021. (AP Photo/Matt Rourke, File)

Health chiefs in the US and the UK have approved the rollout of vaccines with bolstered Omicron-fighting abilities, and Israel is expected to follow suit.

In the UK, the Medicines and Healthcare products Regulatory Agency approved Pfizer’s updated shot on Saturday, and Moderna’s last month. In the United States, the Centers for Disease Control and Prevention endorsed both updated shots on Thursday.

Israel hasn’t announced a timeline for the new shots, though as a vaccine-forward nation, they’re expected to be rolled out soon.

Should people due for a COVID shot now wait, in the hope of getting one of the new improved vaccines? If Omicron has changed since the new vaccines were developed, will they even help? The Times of Israel spoke to leading epidemiologist Michael Edelstein, a professor at Bar Ilan University’s medical school in Safed and a former top official in Public Health England, the executive agency of the London-based Department of Health.

“We can be optimistic that Omicron-specific vaccines will deliver advantages over the coming months even if they were built for ‘old’ Omicron strains,” said Edelstein, in a conversation that covered the new shots, vaccines for kids, and COVID prevention.

He said there is still a “race” between new vaccines and new variants, meaning that success in fighting COVID will require producing new updated vaccines quicker than new variants make big changes to the virus. But he was upbeat. He commented: “We have come a long way in terms of understanding the disease, how it spread, how to prevent and treat it, and how to balance the individual and collective risks the disease presents against being able to carry on living, working and traveling.”

The Times of Israel: Vaccines are changing, and both America and the UK have approved shots that have been updated to better confront variants. They are adjusted for early strains of Omicron, but since their development, new Omicron subvariants have emerged. Will they still be useful?

Michael Edelstein: We don’t have trials that show whether vaccines that are tailored to early Omicron work well against later strains, but we have cause for optimism. This is because, in the case of natural immunity, recovering from early Omicron strains does seem to generate strong protection against later strains. We have seen this in peer-reviewed data from Portugal, which assessed the extent to which getting infected with the first Omicron protected people from later variants. In view of this, we can be optimistic that Omicron-specific vaccines will deliver advantages over the coming months even if they were built for “old” Omicron strains.

A woman receives a fourth dose of the COVID-19 vaccine at Clalit Health Services in Mevaseret Zion, Jan. 11, 2022. (AP Photo/Maya Alleruzzo)

What do we know today about the relative benefits of the third and the fourth vaccine doses? We often refer to both as boosters, but they seem to perform a different function in terms of immunity. Can you explain this?

As the pandemic has progressed, it’s become clear that the third dose, while initially seen as “extra” protection, is actually essential for deriving the full benefits of vaccines. Only with a third dose are we getting anything close to maximum protection against severe disease — and the benefits in preventing severe disease are long-lasting.

The fourth dose is a different story. It adds to protection against both infection and serious disease, but the increase in the added protection is quite short-lived. Health officials in Israel say that fourth doses have saved lives and they are right — they were given to vulnerable populations at times of very high virus circulation, and therefore this temporary boost saved lives. But the extra protection only lasts for around five months.

Epidemiologist Michael Edelstein (courtesy of Michael Edelstein)

If this is the case, is it right to talk about both third and fourth doses as “boosters”?

The only reason we talk about third doses as a booster is that the initial vaccination dose, based on what we knew at the time of initial rollout, was two shots. Now, we know the importance of third shots, and some vaccine experts think we should actually refer to the third shot as part of the initial regimen, and only subsequent shots as boosters.

Whatever names we use for the third shot, I think it’s important to stress its effectiveness, and urge anyone who is eligible but hasn’t received it to do so.

Some people in Israel who are eligible for another dose are wondering whether they should wait. They see the rollout of variant-specific vaccines in the US and elsewhere, and think it could be worth holding off their next dose until such vaccines arrive in Israel.

If we knew exactly when updated vaccines are arriving and who they will be allocated to, it could be argued that waiting makes sense, but in reality we know neither of these things. Anybody at high risk, because of age profile or medical background, should be sure to take the recommended vaccines on time without waiting. For such people, waiting would be a risky strategy.

What about for adults who aren’t considered high risk?

For others, it’s a more personal decision, and it’s hard to predict the advantages and disadvantages of waiting. The virus continues to circulate and you just don’t know when you’re going to be exposed. For those who are less high risk, you can try to calculate when the optimum time is to take another shot, but there is a lot of speculation that goes into such a calculation.

This summer Israel approved COVID vaccines for children from six months, meaning that now, everyone apart from very young babies is eligible. What insights can you offer, based on what we know today, regarding vaccines for children?

The individual benefit for children is not as clear as with adults because of the lower severity of COVID-19 in children. However, it is worth remembering that there are still children who become severely ill. In addition, vaccination among children enables schools and kindergartens to continue functioning in the event of future waves. Vaccinating children also reduces the risk of them infecting other more vulnerable people around them.

An Israeli boy smiles after receiving a dose of the Pfizer-BioNTech Covid-19 vaccine at the Meuhedet Healthcare Services in Tel Aviv on November 22, 2021, as Israel began its coronavirus vaccination campaign for 5 to 11-year-olds. (JACK GUEZ / AFP)

Experts stress that vaccines are part of a wider COVID prevention strategy that also includes other measures. In Israel, this meant a recommendation for masks to be worn indoors when cases were high. What do we know today about masks and other measures?

Masks have been shown to reduce transmission when worn properly — in particular they reduce the risk of infected individuals, who may not know they have COVID, infecting others. This is particularly true indoors and this is why, in hospitals, where there are many vulnerable individuals in a closed space, masks continue to be mandatory.

Air circulation is important and can help mitigate infection risks. Open windows can help in indoor spaces. Outdoors, infection risks are reduced, but are not eliminated. When people are at close proximity, even outside, there could well be a risk of infection.

What is your general assessment of the impact of vaccines on the pandemic?

Almost two years since they appeared, vaccines have made a tremendous impact on the pandemic by reducing transmission and reducing the risk of severe disease, even if they have not been the magic solution some people had hoped for. The new updated vaccines will help protect better against newer strains, even though we have something of a race between vaccines and new strains. We have come a long way in terms of understanding the disease, how it spreads, how to prevent and treat it, and how to balance the individual and collective risks the disease presents against being able to carry on living, working and traveling.

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