Release second doses to speed vaccinations
Supply will rapidly expand to meet needs
As of Monday about 9 million Americans, according to the Centers for Disease Control and Prevention, have received the first dose of a COVID-19 vaccine, which is far below the goal of vaccinating 20 million people by the end of 2020.
The slow vaccine rollout is occurring at the same time the United States is enduring record levels of infections and deaths.
To accelerate vaccinations, some have proposed to delay the timing of the second dose. Critics of this approach argue that it lacks clinical evidence and may weaken the public’s confidence in vaccine effectiveness.
In the absence of additional clinical trial data to support changing the timing of doses, the Food and Drug Administration strongly recommends following the authorized dosing schedule for the current COVID-19 vaccines.
A related issue is that Operation Warp Speed and hospitals have held back vaccine doses to ensure those who have received the first shot will have guaranteed access to the second. Operation Warp Speed is holding back more than half of the vaccine inventory for second doses.
At the same time, hospitals also are holding back second doses. The practice is well-meaning but traps up to 85% of our life-saving vaccine doses in warehouses and hospital freezers.
As supply chain experts who have followed closely the COVID-19 vaccine rollout, we believe that at this early stage, Operation Warp Speed and health care providers should not hold back the second doses.
Our recommendation is based on our analysis of how vaccine supply will change in the coming months, the way vaccines are administered in practice, and how the supply of and demand for vaccines evolve over time.
Supply disruptions are unlikely
First, holding back a significant proportion of doses makes sense only when the supply is expected to decrease because of manufacturing and supply chain disruptions.
While supply disruptions are a real possibility, the likelihood of such a scenario is relatively low. Both Pfizer and Moderna are ramping up their vaccine production, and we expect to see an uptick in the coming months, which means there is little reason to hold as much as half of vaccine doses to protect against production glitches.
Second, most people who receive a first dose are immediately scheduled for their second vaccine appointment. So even if future supply is lower than anticipated, the system can be designed to prioritize those who have received their first doses over those who have not.
No need to hold back doses now
In essence, even if vaccine supply remains flat, most health care providers will still be able to satisfy the need for second doses. By not holding back doses, more people can receive their first doses earlier, which maximizes the power of COVID-19 vaccines to end the pandemic.
Third, the decision to hold back second doses depends on the stage of COVID-19 vaccination. We are at the beginning of the vaccination process, and both supply and demand will rapidly expand in the coming months.
It makes little sense to hold back doses at this point. Holding back a significant proportion of doses makes sense only when supply is expected to be flat and the demand is expected to grow, a situation we may encounter in the late spring when the general population has access to COVID-19 vaccines.
The ongoing debates about whether we should give everyone only a single dose or delay the second dose are based on false tradeoffs. A more urgent problem is to reexamine the significant proportion of COVID-19 vaccines that have been held back.
We are glad to see that the problem is on President-elect Joe Biden’s radar and his team plans to reverse the holdup strategy. On Tuesday, the Trump administration also signaled that it will now encourage states not to keep second doses in reserve.
In the unlikely event that future supply becomes more constrained due to supply disruptions, we can at that point decide whether to prioritize those who need a second dose or use the limited supplies for vaccinating more people with the first dose.
But for now, we do not need to, nor should we, make that decision. Too much is at stake. Tinglong Dai is an associate professor of operations management and business analytics at the Johns Hopkins University Carey Business School. Prashant Yadav is a senior fellow at the Center for Global Development and a lecturer on Global Health and Social Medicine at Harvard Medical School.