Prioritizing the elderly for COVID-19 vaccines doesn’t make sense, but giving the first shots to young superspreaders could be a shortcut toward “herd immunity,” an Israel Prize-winning scientist has claimed.
Health services internationally are planning how exactly they will allocate the first batches of vaccines that they receive, following Pfizer’s announcement last week that its coronavirus shot appears to be 90 percent effective, and Moderna’s announcement Monday that it is hitting 94.5%.
But for the sake of public health, social butterflies are a far better investment, says Prof. Shlomo Havlin, a pioneer of statistical physics, who insists that the idea of starting with elderly people like him just doesn’t make sense.
“It would be much more effective to immunize the potential spreaders,” he told The Times of Israel on Sunday. “This way they won’t infect others and the pandemic will decay much faster.”
The 78-year-old Bar Ilan University professor said that’s the best route toward herd immunity, arguing: “It’s not the kind of idea that will be popular, and you would think that it wouldn’t be good for me, as an older person, but it would actually benefit everyone.”
Havlin’s latest study, which he says illustrates his logic, has been peer-reviewed and will soon be published in the journal National Science Review.
No matter how fast the vaccine producers work, all countries are expected to receive their vaccines in batches. The director-general of the Health Ministry reportedly moved to manage expectations on Monday, according to Army Radio, telling ministers that only 100,000 Israelis will receive the necessary two doses of the coronavirus vaccine ordered during the first quarter of 2021.
Havlin, who is renowned for developing the first mathematical evaluation theory for the stability of the internet, said of his proposal: “If you don’t have enough vaccine and you want to protect the whole population, this is the only way to do it.”
The principle is simple, he insisted, noting that it has been shown worldwide that huge percentages of infections are spread by a small number of people referred to as superspreaders who move around a lot.
“Those who don’t move around much, like me, can be infected but can’t really infect many others,” he said. “So it’s good for me, but isn’t really so good on a national level, if I get the vaccine.”
This argument, though absent from public discussions among health officials, has been raised a few times in academic circles. Three health experts from Johns Hopkins University and the University of Southern California argued in a September article that the elderly should wait until potential superspreaders receive shots. But their claim was very conceptual; they offered no stats to show the bottom-line benefit.
Havlin has advanced the argument by building a complex model that he says predicts the advantages of inoculating potential superspreaders first, and by suggesting how that could be carried out.
His conclusion: Societies will get three times the benefit from their initial batches of coronavirus shots if they are administered to potential spreaders, instead of the elderly and vulnerable.
“This is a very big difference,” he said. “If it were a 10 percent or 20% difference in effectiveness you could say it’s not so important, but the figure we see is significant. This is because in society many people have few encounters while a few people have lots of encounters.”
Havlin is convinced that identifying the high-encounter people is easier than imagined. Cellphone data could make it very simple, though he admitted that privacy laws make it unlikely the information would be handed to health officials.
But they could start with people in jobs that, by their nature, involve lots of face-to-face contact. Many countries plan to vaccinate health workers; he suggested including teachers, retail employees and others whose professional profile indicates exposure to large numbers of people.
Havlin also wants to seek out society’s social butterflies and immunize them, which he said would be easy. One method he suggested was to send researchers to any public place, gather 10 people, give them a questionnaire that assesses their level of social interaction, and vaccinate the most sociable person in each such group.
Havlin created a mathematical model to see what would happen in society if such a questionnaire method were deployed. His upcoming journal article consists mostly of findings from this modeling, with the conclusion that initial shots of a vaccine would have triple the impact in cutting cases in a society.
Politically speaking, it would be an uphill struggle to opt for such an approach, Havlin admitted. “It’s not easy to implement,” he said. “For example, how can Bibi say, ‘I won’t give immunization to older people’? Many won’t understand.”
However, he said, the potential benefits of his approach could be worth going out on a limb for.
Eran Segal, a Weizmann Institute computational biologist whose coronavirus projections are closely followed by Israelis, estimated that if Israel obtained around 500,000 vaccines, expected in January or February, it could reduce the number of serious cases by 40%.
His projections were based on the assumption that available vaccines are used to inoculate the oldest members of society: The first 500,000 vaccines could protect Israelis over 75, and 800,000 could immunize all those over 70.
Segal, reached by The Times of Israel to comment on Havlin’s superspreaders-first idea, said that some such people are identifiable but others aren’t, which presents a challenge.
He suggested that a hybrid vaccination model may have potential. “It could very well be that a combination of vulnerable and superspreaders would work better,” Segal said.