The vaccine, called Jynneos, is approved as a two-dose regimen, but most people at risk of infection have received one dose — if they can find it. Now the shortage has led federal officials to consider a rarely used approach: a so-called dose-saving strategy, which gives shots that each contain only one-fifth of a dose. For most recipients, one dose should be enough to prevent serious illness, and there is some evidence that even smaller doses may be effective. But preliminary research suggests that people with HIV or other conditions that weaken the immune system may be less protected than people without such diseases, according to some experts. “A dose is better than none,” said Dr. Alexandra Yonts, an infectious disease physician at Children’s National Hospital in Washington, DC, but people with “HIV and other immunocompromised people should be aware that they may not have an adequate level of protection against infection, even with vaccination,” she added. Even two weeks after the vaccine, when the antibody response is ongoing, immunocompromised people may need to “use all other precautions to prevent exposure, according to public health guidelines,” he said. The findings also suggest that some men should be prioritized for full vaccination. Given supply constraints, this can be difficult. Federal officials have ordered nearly seven million doses of Jynneos, but the shots won’t arrive for months. So far, the Biden administration has sent about 600,000 doses to states. He said last week that 800,000 additional doses had been given to states, but distribution could take weeks. Faced with shortages, some cities, including Washington and New York, are limiting second installments to stretch their supplies. Food and Drug Administration and CDC officials disagreed with that strategy, noting that Jynneos is approved as a vaccine given in two doses 28 days apart.
What you need to know about monkeypox virus
Card 1 of 7 What is monkey pox? Monkeypox is a virus similar to smallpox, but the symptoms are less severe. It was discovered in 1958, after outbreaks in monkeys kept for research. The virus was found mainly in parts of Central and West Africa, but in recent weeks it has spread to dozens of countries and infected tens of thousands of people, the vast majority of them men who have sex with men. On July 23, the World Health Organization declared monkeypox a global health emergency. How does it spread? Monkeypox virus can be spread from person to person through close physical contact with infected lesions or blisters, by touching objects – such as clothing or bedding – that have previously touched the rash, or through respiratory droplets produced by coughing or sneezing. Monkeypox can also be transmitted from mother to fetus through the placenta or through close contact during and after birth. I’m afraid I might have smallpox. What should I do? There is no way to test for monkeypox if you only have flu symptoms. But if you start to notice red lesions, you should contact an urgent care center or your primary care doctor, who may order a monkeypox test. Isolate at home as soon as you develop symptoms and wear high-quality masks if you must come into contact with others for medical treatment. What is the treatment for monkey pox? If you do get sick, treatment for monkeypox generally involves managing the symptoms. Tecovirimat, an antiviral drug also known as TPOXX, may occasionally be used for severe cases. Jynneos vaccine, which protects against smallpox and monkeypox, can also help reduce symptoms, even if taken after exposure. I live in New York. Can I get the vaccine? Adult men who have sex with men and who have had multiple sexual partners in the past 14 days are eligible for vaccine in New York, as well as close contacts of infected people. Eligible individuals who have conditions that weaken the immune system or have a history of dermatitis or eczema are also strongly encouraged to get vaccinated. People can book an appointment through this website. But as federal health officials declared a public health emergency on Thursday, Dr. Robert Califf, FDA commissioner, said the agency is now considering approving shots that contain only one-fifth of the normal dose, given between the layers of the skin. from below it. The FDA would need to grant Jynneos emergency use authorization in order to be administered in this manner. The dose-saving approach has been used when supplies of other vaccines are scarce. But giving intradermal vaccines requires more skill than more traditional vaccinations. One dose is probably enough to prevent severe symptoms in most people, and the dose-saving strategy can work just as well. But it’s unclear whether a reduced regimen is enough to prevent infection and, if so, how long that immunity might last, federal health officials said. “We’re in a no-data zone,” said Dr. Emily Erbelding, an infectious disease expert at the National Institutes of Health who has overseen trials of Covid vaccines in special populations. An often-cited statistic says that the vaccine is 85 percent effective against monkeypox. These data did not come from Jynneos’ trials, but from a small 1988 study that looked at the incidence of monkeypox among people who had been vaccinated for smallpox earlier in life. No large clinical trials of Jynneos as a monkeypox vaccine were conducted in humans before its approval. Instead, the FDA relied on measures of antibody responses in small groups of people after immunization with Jynneos compared to those produced by ACAM2000, an older smallpox vaccine. In studies conducted by its manufacturer, Bavarian Nordic, two doses of Jynneos produced antibody levels in humans that were about the same as those after one shot of ACAM2000. Antibody levels after the first dose of Jynneos initially rose for two weeks and then remained stable until the second dose four weeks later, when they rose to very high levels — higher than those recorded with ACAM2000. Scientists read that means if the first dose is not followed by a second, the protection may not be long-lasting. “Ideally, a second dose would be given if protection for longer than that four-week period is desired,” said Dr. Yonts, who reviewed the data for the FDA as a staff scientist. He added that delaying the second installment to eight weeks might make sense. “But if it’s going to be about six months, then I think the prioritization would lean more toward those who are more severely immunocompromised,” he said. Injecting one-fifth of a regular dose of Jynneos between the skin layers, as the FDA suggested Thursday, may be effective, according to limited research. The skin has much more than immune cells that respond to vaccines. But the research is very limited. Scientists at the NIH had planned to test the dose-saving strategy in a clinical trial starting in a few weeks. It is unclear whether these plans will be shelved or accelerated. Information about how Jynneos works in people with HIV, particularly in people with severe immune problems, was already scarce. In a study conducted by Bavarian Nordic, the antibody response to vaccination tended to wane: 28 days after the first vaccination, 67 percent of HIV-infected individuals produced antibodies, compared with 84 percent of uninfected individuals. While Dr. Yonts said the data from that trial was inconclusive, as a reduced antibody response is often seen among immunocompromised people receiving other vaccines. When evaluating Covid vaccines, for example, researchers found that HIV patients were more likely to have unprecedented infections. “Additional doses of common vaccines are recommended for people with severe or moderate immunosuppression,” said Keri Althoff, an epidemiologist at the Johns Hopkins Bloomberg School of Public Health, who led the Covid vaccine study. “As immune suppression increases, response to vaccines decreases.” The CDC and the New York Department of Health say Jynneos is safe for people with HIV, but the agencies have not tested its effectiveness in this population. In contrast, health officials in Britain say that for people who “are HIV positive or have any other condition or treatment that results in a weakened immune system, the vaccine may not protect you as well.” The vaccine’s package insert also notes that immunosuppressed individuals “may have a reduced immune response.” “Two shots can be very important in this population, which is not really the case in public health response,” said Dr. Chloe Orkin, an infectious disease specialist at Queen Mary University of London, referring to immunocompromised people. However, until more doses are available, state and local health departments may not have much choice but to stick to reduced regimens. “In a shortage environment, we must do everything we can to bring the benefits of the vaccine to the city as quickly as possible,” Patrick Gallagher, a spokesman for the New York City health department, said in a statement.
