An ‘ideal’ model of annual vaccination against COVID

Lionel laurent

Two doses? Three? Plus? The euphoria with which the safe and effective vaccines against COVID-19 A year ago it has turned into confusion and debate in the face of resurgence of cases and a nasty new variant. The rich world is redoubling its efforts to get booster doses, ignoring the warnings of the World Health Organization (WHO) that this will worsen supply shortages in the developing world.

The companies that brought us the wonders of mRNA – Modern Inc. and Pfizer Inc. – aren’t sure of much, except for one thing: It seems that the need for vaccines won’t stop anytime soon. Stephane Bancel, CEO of Moderna, warned that vaccines may need a readjustment against the omicron variant next year, while Pfizer CEO Albert Bourla proposed a schedule of vaccines each year to maintain a “level of very high protection ”over time.

The idea of ​​an annual vaccine against COVID sounds, in theory, quite similar to vaccines against influenza, which are adapted each year to deal with new variants. But in reality, even countries with bulging wallets face difficulties with bottlenecks as what started as a single nationwide rollout turns into several.

In France, where there are now 19 million people eligible to receive a booster dose, on Tuesday there was only availability for about 290,000 seats during the next two weeks since the primary care application Doctolib, according to the media. In the UK, where the minimum period for a booster will be cut in half – three months – doctors reportedly said they are “overwhelmed” and operating at full capacity. That is not a desirable effect.

One possible answer, according to a team of researchers from BarcelonaTech, would involve developing a new planning framework for COVID vaccines: administering doses at a rate fast enough to generate protection, but not so fast that a new one is needed. national vaccination campaign every few months. In other words, an “ideal” strategy, which would work as a continuous cycle, immunizing some people, all the time.

The model imagines various outcomes based on a potential decline in protection over time after a third dose. In this model country – let’s call it Vacunoland – an implementation in which 1% of the population is vaccinated each week provides a low level of protection over a long period of time, whereas a 4% rate would be better, but may require more dose given the rate at which a larger group of people lose protection.

The “ideal” rate proposed by the researchers is 2%, which would mean covering around 80% of the Vacunolandia population in 40 weeks. If we extrapolate this to the region of Catalonia, it would amount to vaccinating between 150,000 and 200,000 people per week, or 10,000 per day. Given that the region has around 400 primary care centers that distribute 30 vaccines each day, the situation seems totally viable.

If we expand it to a population the size of a country, it is clear that France and the United Kingdom could deliver between 1.3 and 1.4 million doses per week. The UK is already over 2 million.

But this would imply a permanent struggle, with the need for greater investment in primary care.

There are other important caveats, since our world is not “ideal.” For countries with less success in promoting vaccine adoption, even a 2% rate seems exaggerated. Romania and Bulgaria, which are among the countries with the lowest vaccination rates in Europe, have failed to reach this level for most of the year. Demand is a problem in countries with a great reluctance to vaccines, and compulsion is a policy that has yet to be really tested.

Supply is the other big problem in the developing world. South Africa, where the omicron variant now appears to be dominant, is not even close to a 2% weekly rate.

And there is also the risk that future variants, be it omicron or others, will escape the best-thought vaccination plans of public health authorities.

However, if annual vaccinations end up being the norm, the “ideal” model has advantages. It would be easier to explain and implement than the current swing between crisis and complacency. There could be less confusion – and cynicism and fatigue – if, instead of talking about booster shots, third doses, and modified vaccines, there was a once-a-year mentality.

This kind of “fairy tale” thinking could end up humiliated by the reality of COVID, of course. But policymakers should start working on all possible endings to the pandemic, even happy endings.