Toby Gould was an early adopter. In September, Mr. Gould, 78, went to a pharmacy in Hyannis, Mass., to get one of many new vaccines for respiratory syncytial virus, referred to as R.S.V. He has bronchial asthma, which might heighten his threat of great sickness if he had been to be contaminated.

Carol Kerton, 64, knew R.S.V. might be harmful: Her 3-year-old granddaughter had such a extreme case that she was taken to an emergency room. Ms. Kerton was vaccinated in September at an area grocery store in Daytona Seaside, Fla.

Sam Delson, 63, obtained the R.S.V. vaccine final month in Sacramento. His physician beneficial it, he stated, “as a result of I’m over 60 and have a considerably weakened immune system” after a long-ago bout with most cancers.

They’re the exceptions. To date, solely about 15 % of People over 60 have obtained one of many two new R.S.V. pictures, which the Meals and Drug Administration accepted in Might and are the first-ever vaccines towards the illness. Simply 16 % extra stated they undoubtedly deliberate to, based on the Facilities for Illness Management and Prevention.

Against this, greater than 62 % of adults over 65 have obtained the beneficial flu shot this fall, and a 3rd have gotten the up to date Covid-19 vaccine.

“It’s a brand new vaccine, and individuals are making an attempt to determine whether or not they want it or not,” stated Dr. Preeti Malani, a geriatrician and infectious illness specialist at College of Michigan Well being.

That’s in the event that they know in regards to the R.S.V. vaccines in any respect. A nationwide survey this summer season of individuals ages 60 by way of 80 discovered that almost half hadn’t heard about them.

The C.D.C. recommends the R.S.V. vaccines for individuals over 60, after having particular person discussions with their well being care suppliers, one thing known as “shared medical decision-making.” Medicare Half D, Medicaid and most non-public insurers will cowl the whole price.

The truth that older individuals are weak to R.S.V. is an unfamiliar idea to many individuals. For many years, the virus was principally thought of a menace to infants and younger kids. Most physicians, “once they went to medical college, had been taught that R.S.V. was a pediatric sickness,” stated Dr. William Schaffner, an infectious illness specialist at Vanderbilt College Medical Middle. “It’s nonetheless the main reason for hospitalization in infants within the U.S.”

However the F.D.A. estimates that the virus sends 60,000 to 160,000 individuals over 65 to hospitals every year and causes 6,000 to 10,000 deaths. Different revealed estimates are even larger.

“It’s a very contagious virus,” Dr. Malani stated. Although kids can change into fairly unwell, extra typically, “a 4-year-old with a runny nostril might have R.S.V. and never change into very sick; it appears to be like like an everyday chilly,” she stated. Nonetheless, she added: “The grandparents might get pneumonia.”

The danger of turning into critically unwell from R.S.V. will increase markedly with age. Hospitalization charges rise sharply for these of their 70s and 80s, particularly for these with power coronary heart and lung ailments like bronchial asthma, coronary heart failure and power obstructive pulmonary illness. Older adults who’ve diabetes or liver and kidney illness, or weakened immune programs, additionally face larger threat. Adults will be contaminated repeatedly, and there’s no drug that ameliorates the illness, as there’s for the flu and Covid-19.

A examine revealed in The New England Journal of Medication in 2005 adopted sufferers over 4 winters and reported that, amongst high-risk sufferers (their common age was 70) with coronary heart failure or pulmonary illness who contracted R.S.V., 16 % required hospitalization. In one other cohort of older sufferers hospitalized with respiratory signs (with a mean age of 75) and identified with R.S.V., 15 % wound up in intensive care.

The brand new R.S.V. vaccines are extremely efficient. Medical trials outcomes confirmed that Arexvy, the shot made by GSK, was 94 % efficient towards extreme sickness in older adults. Pfizer’s shot, known as Abrysvo, was 86 % efficient towards extreme sickness.

So why haven’t the vaccines caught on extra with their supposed recipients?

One cause: A shared decision-making suggestion from the C.D.C. can depress vaccination charges, Dr. Schaffner stated, as a result of “you’ll be able to’t market it with fairly the depth and assurance as with a blanket suggestion” — just like the one recommending flu pictures for everybody over 6 months previous.

Additionally, older individuals now obtain a number of public well being messages about seasonal vaccinations. “A number of years in the past, we had been all recommending one vaccine every winter — flu,” Dr. Schaffner stated. “We haven’t but organized ourselves to be persuasive in getting individuals to just accept three seasonal vaccines,” for influenza, Covid-19 and now R.S.V. (Getting two or three on the identical time is ok, the C.D.C says.)

When R. Jessica Jones, 76, who lives in Haiku, Hawaii, texted her physician about seasonal vaccinations, he replied that she ought to get the Covid-19 booster and a flu shot, however that getting an R.S.V. vaccine was “optionally available.”

Ms. Jones, stunned, requested why. He advised her he thought the information on their security and efficacy was “restricted” (the F.D.A. disagreed), so she skipped getting one.

“When suppliers are confused, sufferers are additionally confused,” Dr. Malani, of College of Michigan Well being, stated. “If we actually need uptake within the inhabitants that would profit, we have to present clear info to docs and others.”

Whereas some well being care suppliers hope to enhance the vaccination price amongst older People, the vaccines’ producers are apparently delighted with the variety of individuals looking for out the pictures so quickly after delivery them to pharmacies, hospitals and docs’ workplaces final summer season. The producers are amassing knowledge on the vaccines’ effectiveness and negative effects and — a central unanswered query — how typically individuals will have to be revaccinated to keep up safety.

“For a brand new class of vaccines, that is actually unbelievable,” stated Dr. Len Friedland, who directs public well being for GSK Vaccines.

“There’ll at all times be hiccups,” he stated. “However generally it’s gone very properly, and we’re not listening to that there are entry issues for sufferers.”

Dr. Nathaniel Hupert, co-director of the Cornell Institute for Illness and Catastrophe Preparedness, was extra cautious. Fifteen % is “loads higher than zero,” he stated, declaring that till final summer season, there was no prevention obtainable towards R.S.V. However, he stated, “when you’d prefer to stamp out R.S.V., that’s not going to occur with this stage of protection.”

Different producers have R.S.V. vaccines in improvement, and older People could ultimately have higher safety as extra pregnant ladies and infants are immunized, because the C.D.C. recommends. “Children have the distribution franchise for these respiratory viruses each winter,” Dr. Schaffner, of Vanderbilt College Medical Middle, stated.

Over time, “we’ll in all probability see much less R.S.V. transmission from youngsters to their grandparents,” Dr. Hupert stated. “However we’re not there but.”