According to a New York Times analysis of Centers for Disease Control data from early March until April 9, close to 8 percent of those who received their first shot of the Pfizer and Moderna candidates did not receive a second. While a 92 percent follow-through rate is quite impressive compared to other vaccinations — it’s closer to 75 percent for adults receiving the two-dose shingles vaccine — that still means some 5 million Americans did not receive shot No. 2. Coming back for that second dose is essential to the way the mRNA vaccines operate; without it, patients are more susceptible to virus variants and experience weaker immune system responses.
While the Times reports that some recipients are choosing not to show up for their second appointment — “I didn’t really feel the urgency to get that second dose,” one man in Chicago told the paper — a larger concern than fear of side effects is cancellations by providers who ran out of shots:
In some cases, problems with shipments or scheduling may be playing a role in people missing their second doses. Some vaccine providers have had to cancel appointments because they did not receive expected vaccine deliveries. People have also reported having their second-dose appointments canceled or showing up only to find out that there were no doses available of the brand they needed.
Some people can be flexible about being rebooked. But that’s harder for people who lack access to reliable transportation or who have jobs with strictly scheduled hours, said Elena Cyrus, an infectious disease epidemiologist at the University of Central Florida.
The increasing no-show rate, nearly double that of the first few weeks of the campaign, is one of several major challenges facing states and the Biden administration, following the impressive success of the vaccination rollout in his first 100 days, a period in which over 200 million doses were administered. Now that the most eager vaccine recipients have signed up for their doses, public-health officials must find ways to bring shots to more hesitant and harder-to-reach populations. And while the return of the one-shot Johnson & Johnson candidate will aid the vaccination effort, the pause over its extremely rare, but very serious, blood clots in recipients could increase hesitancy among those who have yet to get a shot: According to one recent Harris poll, 54 percent of respondents said they would not be willing to receive the J&J vaccine after its suspension.