Since the start of the Covid-19 pandemic, clinical science and public health have operated in tension over policy. Clinical science pertains specifically to disease in an individual patient; public health focuses on groups of people and therefore considers strategies that optimize societal benefits and minimize the risks, health and otherwise, that affect the well-being of a community. The contrasting perspectives of science and public health are now playing out in the discussion of the Covid-19 vaccination program in the U.S.
Over the past two months, two Covid-19 vaccines have received emergency-use authorization on the basis of the results from clinical science—i.e., a randomized-controlled trial (RCT). Pure science says that to get the maximum benefit of the vaccines, two doses, three or four weeks apart, are essential. The Phase 3 RCTs for the vaccines (both mRNA vaccines) demonstrated that after two doses, the vaccines were more than 90 percent efficacious (referring to outcomes of the RCT) preventing serious infection. It was observed, however, that after one dose, the efficacy was about 52 percent. Data on the length of time that protection lasts for one dose or two is limited (this information will be available when the trials are finally completed), though it is strongly believed that those who received the second dose have significantly longer protection.
Epidemiologic science says that health-care personnel and residents of long-term care facilities should be vaccinated first, followed by people over 75 and frontline essential workers. The epidemiology of Covid infections and deaths justifies these recommendations. It almost goes without saying that health-care professionals exposed all day, every day should be among the first to be vaccinated. Residents of nursing homes are at substantial risk for becoming infected and dying from Covid. The risk for infection among those between 75 and 85 is eight times greater than for adults under 30, and the risk of death is 220 times greater. By contrast, the rate of infection among those even slightly younger—the 65-to-74 cohort—is five times greater than among the 18-to-29 age group, and the risk of death 90 times greater.
Unfortunately, the start of the vaccination program has been slow, which is worrisome given the high numbers of current Covid cases. The past seven days saw more than 1.7 million cases. During this period, the U.S. has experienced between 3,500 and 4,000 Covid-related deaths per day and, in many regions, severely limited hospital capacity. To put this in perspective, at the start of the pandemic last spring, the number of Covid-related deaths per day was between 2,000 and 2,500. Rollout for the vaccines started last month, and the targets for numbers of people vaccinated have not met expectations. As of January 14, the federal government has distributed 29.3 million vaccines, and the number of people receiving first doses stood at 10.2 million—still well short of the goal of administering 20 million first doses by December 31, 2020. The rate of vaccination has picked up, though.
In reaction to the sluggish start of the Covid vaccination program and the growing number of deaths and hospitalizations, Operation Warp Speed officials are moving to a more public-health-oriented perspective. They are making plans to distribute their full store of purchased vaccines immediately, rather than holding back some of the vaccine for second doses, and they are recommending that states lower the age cutoff to 65. Both strategies are intended to increase the number of people vaccinated—if only partially—in hopes of reducing the impact of Covid sooner.
The officials assume that vaccine production and distribution will ramp up sufficiently to provide timely administration of the second dose. Britain’s most recent vaccination plan also includes the release of its entire vaccine supply, though British public-health authorities are less optimistic about acquiring sufficient additional vaccines and are planning for a delay in the second dose. They are making the reasonable assumption that getting more people with one dose sooner is more important than getting fewer people two doses.
Expanding the number of people vaccinated by accepting younger age groups may sound counterintuitive because the supply of vaccine is limited. But difficulty reaching the elderly and reluctance by some to be vaccinated, combined with concerns that supply could be wasted if it’s not used in a timely manner, has prompted a revision of the initial, clinical-based assumptions. This resembles the Israeli approach. Israel is prioritizing the vaccination for those 60 and over and for health-care workers—but in order to avoid waste, when extra vaccine supply exists, vaccination centers will administer doses to anyone, regardless of age and risk, until the surplus runs out.
The number of Covid cases and deaths stand at all-time highs. Concerns that this trend will continue for the next few months is motivating policymakers to broaden their thinking from a pure science approach to one that uses science to create rational public-health policies. Expanding the eligible populations and pushing out the country’s full supply of vaccine despite the risk that the supply of second doses is insufficient illustrates how public-health can act as the real-world expression of science.
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