The real Contagion: governments face agonising decisions about who to vaccinate first

“We may never know where this disease came from. But we do know that this vaccine is a result of the courage and perseverance of a remarkable few. We shall now begin the drawing [of birth dates]...”

This is the sombre scene on day 133 of the film Contagion (2011), a fictional but now familiar account of a deadly droplet-spread virus that wreaks havoc around the globe.

A vaccine has been found and the US president presides over a birthdate lottery to decide who should get it first. The first batch of MEV-1 vaccine goes to those born on March 10 (a one in 365, or 0.27 per cent, chance).

The scenario sounds far-fetched but as experts across the globe consider vaccine allocation strategies, something similar may yet emerge as an option for the general population at least.

“Once you have covered the priority groups, health workers and the most vulnerable, and you try to roll it out to the remainder of the population, there has to be some acceptable and equitable way to do that,” says Professor Ian Lipkin, the John Snow Professor of Epidemiology at Columbia University and the principal scientific adviser to the film.

“You could use a random number generator, or you could select birthdays as we did in the film. We used birth date lotteries for the [military] draft in the United States; who was going to go to fight and who wasn’t. This is obviously a different kind of lottery.”

A lottery was not discussed at a pivotal meeting of the Joint Committee on Vaccination and Immunisation (JCVI) on September 1, but the 48 scientists and officials in virtual attendance were grappling with the same problem: how should a Sars-Cov-2 vaccine be distributed in the UK - and who should get it first?

The stakes could hardly be higher. “The value of the vaccine to the UK alone could be in the billions and possibly trillions of pounds”, noted one of three modelling scenarios experts were presented with. Get the strategy wrong and the country could be bankrupted, was the unspoken corollary.

The strategy currently being pursued by the JCVI focuses initial distribution of a vaccine on 11 groups stratified by age, occupation and medical risk. An updated version is expected to be approved by ministers in the next few weeks.

“Older adults’ resident in a care home and care home workers” are at top of the current list, followed by “all those 80 years of age and over and health and social care workers”. Those 75 or older are next, then those over 70 and those over 65.

“High and moderate risk adults under 65” come next, jumping ahead of healthy seniors. The final group - healthy under 50 - is simply listed as “rest of the population (priority to be determined)”.

On the surface, the strategy appears simple, but beneath the bonnet all sorts of complexities and awkward political decisions lurk.

If risk is to be a determinant of who gets the vaccine first, then an array medical and social factors including sex, occupation, ethnicity and income immediately enter the equation, the minutes of the September 1 meeting show. There was even talk of using an algorithm developed by academics at Oxford university to do the heavy lifting.

“Members noted an update from DHSC on the individual risk tool developed by the University of Oxford. It was noted that the tool would identify an individual’s risk of hospitalisation and mortality and could be used to stratify the population”.  The logic of sifting by total risk is compelling but the logistics are difficult, note officials.

According to Public Health England (PHE), twice as many working age men diagnosed with Covid have died compared to women; mortality rates in the poorest areas are double those in the wealthiest; and BAME communities have between a 10 and 50 per cent higher risk of death even once age, sex and social deprivation are taken into account.

Occupation also matters. Low skilled workers have a death rate almost four times that of professionals, with taxi drivers, chefs, bus and coach drivers and sales assistants among the worst affected. For security guards - the hardest hit of all in the first wave - recorded deaths were almost twice that of men working in social care.

Mark Jit, professor of vaccine epidemiology at the London School of Hygiene and Tropical Medicine and lead author of the first paper to model the economic impact of a vaccine on Covid, says that beyond health and care workers, age is a good proxy for risk.

“The risk of dying from Covid goes up so rapidly as people get older,” he says. “And most of the time people with underlying conditions are also older.”

But an age-based strategy is not without dangers. As the European Center For Disease Control notes in an advisory paper on vaccine strategy published on Thursday: “Before pursuing this [age-based] approach, acceptable levels of vaccine safety and efficacy need to be demonstrated among older adults. At this stage, this information is not known”.

Instead, the ECDC recommends an “adaptive” strategy - one which can flex as more is learnt about the jabs and their impact. It should take account of other possible approaches including the targeting of “specific groups”, “density populated areas” and those most likely to spread the virus, including the young.

The US strategy, published by the US National Academies of Sciences, Engineering, and Medicine, reflects this logic. Medical staff are first on its list, followed by older adults living in “crowded settings” and those with multiple pre-existing conditions. Phase three then targets “essential workers” at a high risk of exposure - including teachers, people in homeless shelters and prisons.

“There are multiple vaccination strategies available,” says Devi Sridhar, professor of global public health at the University of Edinburgh. In Australia, for example, experts are considering a “ring vaccination strategy”, similar to that used to combat Ebola, to contain local flare ups.

The difficulty with devising a vaccine strategy is caused by vital holes in our knowledge.

“There are a number of unknown factors about any potential vaccines, and there are still important gaps in our understanding of Covid-19”, says the JCVI.

This is to put it mildly. Will vaccines work in the old or just the young? How long will they last? Will they prevent transmission of the virus or just protect against the worst of it’s symptoms? The answers to these and other vital questions are still not known.

Practicalities are also important given the scale of vaccinating so many people, notes the JCVI, and countries must play to their strengths. But this could also be a trap.

The UK strategy, as currently drafted, bears a strong resemblance to the strategy used for seasonal flu, with age the prime determinant of prioritisation.

But as Prof Sridhar says: “If we are only offering [a vaccine] to the elderly or medically vulnerable, we should be ready and expect the rest of the population to still get Covid”.

Worse, if the vaccine is not tolerated or efficacious in older groups a “plan B” will need to be found fast.

“The prioritisation could change substantially if the first available vaccines were not considered suitable for, or effective in, older adults”, says a note at the bottom of the current priority list.

Timescales are also challenging. The NHS is gearing up to start inoculation of the first ten UK priority tiers from December - some 30 million people - subject to a vaccine arriving.

In a typical year, the NHS vaccinates 15 million for flu in about three months. With the additional resources being brought to bear for Covid, it is just possible that vaccination of priority groups could be complete by late April, should all go to plan.

And then comes tier 11 - the “rest of the population (priority to be determined)” - another 20 to 30 million people. How might they be sifted and brought out of lockdown?

A senior official with detailed knowledge of the JCVI's thinking said that while a US-style birthdate lottery was unlikely, a system based around “year of birth” might work.

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