The newest vaccine against the coronavirus brings America’s public health officials to a very delicate point. Deploying the new shots without careful planning could backfire in ways highly damaging to the fight against the pandemic.

By most measures, the one-dose vaccine from Johnson & Johnson is a gem. It has performed well in clinical trials, proving especially effective against the most severe cases, the ones that put patients into the ICU — if not the morgue. It appears to do well against genetic variants of the virus. Unlike the vaccines from Moderna and Pfizer/BioNTech that received earlier approval from the Food and Drug Administration, the J&J vaccine requires only one visit to a health-care provider, rather than two. It also deploys a different technology against the disease, allowing it to be preserved in ordinary refrigerators rather than super-cold freezers.

But on the headline number — overall effectiveness during testing — the new vaccine lagged behind the two-dose alternatives. Data presented to the FDA showed that the double pokes prevented 90 to 95 percent of covid-19 cases. The new vaccine prevented 72 percent of cases.

Now, these numbers don’t really represent an apples-to-apples comparison. They are different vaccines tested by different scientists on different subjects at different moments in the natural history of the pandemic. Moreover, widespread adoption of a 72-percent-effective vaccine would work wonders against the spread of covid-19, and the comparative ease of a single-dose weapon puts the goal of mass vaccination more quickly within reach.

Still, to the ordinary person’s ear, the new vaccine just sounds . . . not as good. We’ve all been to school. We know that 95 percent is a solid A, and 72 percent is barely a C. Detroit Mayor Mike Duggan (D) gave voice to this common-sense assessment on Thursday, when he declined a shipment of the new stuff. “So, Johnson & Johnson is a very good vaccine,” Duggan said. “Moderna and Pfizer are the best. And I am going to do everything I can to make sure the residents of the City of Detroit get the best.”

Whether that comparison is fully informed or entirely fair, it is going to be made. Therefore, officials need to think carefully about how the Johnson & Johnson vaccine will be used. Initial discussions of the new tool are cause for concern. Some people have suggested that the J&J juice be deployed into underserved communities where residents may have little contact with health-care providers. It’s hard enough to get a single shot into those arms, let alone two, the reasoning goes.

Others have proposed that the new vaccine be channeled into rural areas that lack special freezers for storing the two-dose versions.

Both deployment strategies are dangerously wrong. Polling indicates that poor and rural communities are among the most reluctant to be vaccinated. A poll in November found that fewer than half of Black Americans trust the covid-19 vaccine, while the largely rural Midwest and South have been hotbeds of pandemic skepticism. These audiences are already prone to be leery about government claims. Trying to convince them that the 72-percent vaccine is just as good as the 95-percent vaccines — even, in some ways, better — is unlikely to work.

The nation has reached a very promising, yet precarious, point in the fight against the pandemic. With spring approaching, infection rates falling and vaccination efforts gathering steam, many experts say we are within a few months of bringing covid-19 under control. This is no time for a new controversy about whether certain communities are receiving inferior care.

Fortunately, there is a better way to portion out the vaccines. As long as the one-dose option can be construed as less effective, health officials should direct it toward a population less likely to have trouble with covid-19: young adults. We’ve seen on college campuses and in nightclubs that many of them don’t feel particularly vulnerable to the pandemic. It’s reasonable to assume that their motivation to be vaccinated may be comparatively low. The one-and-done nature of the J&J vaccine will be a selling point.

Now Johnson & Johnson is planning to test its vaccine on 12- to 18-year-olds. If that is successful, they, too, would be good candidates — and perhaps younger children as well, eventually. Many kids are averse to needles. I remember nearly fainting with dread when we lined up in grade school for the new rubella vaccine in the 1960s. Most kids would welcome one shot instead of two.

Eventually, there will be enough vaccine supply for most Americans to have a choice: one dose or two? At that point, everyone — rich or poor, rural or urban, regardless of background or hue — will be able to weigh the pluses and minuses and make a selection. Until then, however, it is crucial to build and maintain public trust in the vaccines. The appearance of unfairness, of steering an inferior treatment into the arms of vulnerable populations, could do terrible damage to the cause.

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