A Goldilocks Model for Yearly Covid Vaccinations

(Bloomberg Opinion) -- Two doses? Three? More? The euphoria that greeted safe and effective Covid-19 vaccines a year ago has turned to confusion and debate in the face of resurgent cases and an ugly new variant. The rich world is doubling down on booster doses, ignoring warnings from the World Health Organization that this will worsen supply shortages in the developing world.

The firms that brought us the mRNA marvels — Moderna Inc. and Pfizer Inc. — aren't sure of much, except for one thing: It doesn't look like the need for shots will stop anytime soon. Moderna Chief Executive Officer Stephane Bancel warned vaccines might need retooling next year against the omicron variant, while CEO Albert Bourla of Pfizer has mooted a course of jabs every year to maintain a “very high level of protection” over time.

The idea of an annual Covid vaccine sounds in theory quite similar to influenza shots, which are upgraded every year to cope with new strains. But in reality, even countries with deep pockets are struggling with bottlenecks as what began as one nationwide rollout becomes several. 

In France, where 19 million people are now eligible to get a booster, only about 290,000 slots were available over the next two weeks from primary-care app Doctolib on Tuesday, according to media. In the U.K., where the minimum gap for a booster is to be halved to three months, doctors reportedly say they're “overwhelmed” and operating at full capacity. This is not a desirable outcome. 

One potential answer, according to a team of researchers at BarcelonaTech, would involve building a new planning framework for Covid vaccinations: Administering doses at a rate quick enough to build protection, but not so quick it requires a new nationwide rollout every few months. A Goldilocks approach, in other words, that would work as a continuous cycle — immunizing some of the people, all of the time.

The model imagines various outcomes based on a potential drop in protection over time after a third dose. In this model country — call it Jabland — a rollout that vaccinates 1% of the population every week brings a low level of protection over a long period of time, while a 4% rate would be better but might require more doses given the pace at which a larger cohort loses protection.

The Goldilocks rate the researchers propose is 2%, which would mean covering around 80% of Jabland's population in 40 weeks. If pasted onto the real-life region of Catalonia, this would be equivalent to vaccinating approximately 100,000 to 200,000 people per week, or 10,000 to 30,000 per day, taking into account weekends, holidays and the inclusion of children. With the region boasting around 400 primary care centers distributing 30 shots per day each, it looks wholly feasible.

Scale it up to a country-sized population, and it's clear that France and the U.K. could manage about 1.3-1.4 million doses per week. The U.K. is already at over 2 million.

But this would require a permanent war footing, requiring more investment in primary care. 

There are other big caveats, given our world is a non-Goldilocks one. For countries with less success in encouraging uptake, even a rate of 2% looks like a stretch. Romania and Bulgaria, among the least vaccinated countries in Europe, have failed to hit this level for most of the year. Demand is a problem in countries with high vaccine hesitancy, and compulsion is a policy that's yet to be really tested.

Supply is the other big issue in the developing world. In South Africa, where omicron now looks to be the dominant variant, the country is nowhere near a weekly rate of 2%. 

And there's also the risk that future variants, whether omicron or others, will escape the best-laid vaccination plans of public-health officials.

Still, if annual shots do end up the norm, the Goldilocks model has advantages. It would be easier to explain and operate than the current oscillation between crisis and complacency. There might be less confusion — and cynicism and fatigue — if talk of booster shots, third doses and tweaked vaccines were replaced with a once-a-year mindset.

This kind of fairy tale thinking might end up humbled by the reality of Covid, of course. But policymakers should start work on all possible pandemic endings — even happy ones.

This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners.

Lionel Laurent is a Bloomberg Opinion columnist covering the European Union and France. He worked previously at Reuters and Forbes.

©2021 Bloomberg L.P.