What’s new with Omicron?

A: IT’S. STILL. TOO. SOON. TO. TELL.

We know, the media panic level has been HIGH this week. But the truth is NO expert or TV pundit can predict what will happen with the new variant Omicron right now. We simply don’t have enough data yet on the key questions about the variant:

1) Is it more transmissible?
2) Can it partially evade existing immunity?
3) Does is cause more severe disease?

It’s going to take at least several weeks to answer these questions. While cases are rising rapidly in South Africa where the variant was first sequenced, this rise is from very low case levels meaning we can’t yet distinguish a true “fitness” advantage from the variant just getting lucky. Time will tell if Omicron can outcompete in places where Delta is highly prevalent. Numerous cases have already been found in Europe without connections to travel in Southern Africa, meaning it may have been circulating there prior to the recent discovery.

The UK and the US have both used the Omicron news cycle to get more aggressive about their booster/3rd dose vaccination campaigns.

🇬🇧 In the UK, the Joint Commission on Vaccination and Immunisation (JCVI) this week approved 3rd doses down to age 18 AND a shortening of the minimum interval since the 2nd dose from 6 month to 3 months. Booster invitations will still proceed by invitation via age prioritization but should steadily work their way down to younger age groups over the next few weeks. The JCVI also (finally) approved 2nd doses for ages 12-15 who are at least 12 weeks past their first dose.

🇺🇸 In the U.S., CDC Director Rochelle Walensky amended guidance that all adults 18 and over SHOULD rather than MAY get a 3rd dose if 6 months after their 2nd dose. Pfizer just requested an extension of their booster EUA to 16 and 17 year olds.

❓Why such a push for boosters?

In addition to evidence that 3rd doses might be what’s required to mount the best overall immune response, booster doses have also been shown to KICK ASS against previously identified variants.

This includes “Beta” which was originally a worrisome variant because it showed more inhibition of antibodies compared to Alpha or Delta (but note that the higher transmissibility of Delta “won” this evolutionary fitness battle and Beta fizzled out).

In the figure below from Pfizer’s booster trial, 3rd doses provided a huge increase in neutralization ability against Beta (the orange bars) compared to two doses. This is why even though variant specific boosters CAN be developed, they might not be needed. Our immune systems after 3 doses may be capable of crushing a variety of the new faces of SARS-CoV-2.