Single dose of Jynneos mpox vaccine reduces hospitalization risk, disease severity
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A single dose of the Jynneos mpox vaccine reduces hospitalization risk and disease severity, a study found, although researchers emphasized that people at risk for the disease should complete the two-dose vaccine series.
According to the study of roughly 6,000 people diagnosed with mpox in the United States, researchers found that 2.1% of vaccinated people and 7.5% of unvaccinated people were hospitalized. The risk for symptoms among vaccinated people before illness onset was also “significantly lower” than those who were not vaccinated.
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“One dose of Jynneos vaccine might attenuate the severity of illness and reduce hospitalization in persons who become infected after vaccination,” researchers wrote in MMWR. “However, to optimize protection, all eligible persons are recommended to complete the two-dose vaccination series.”
As the U.S. mpox outbreak grew in July and August 2022, officials recognized a potential shortage of the Jynneos vaccine and allowed for the use of fractional doses — one-fifth-sized doses delivered intradermally rather than subcutaneously — to extend the supply. Previous study findings published in MMWR indicated that one dose of the vaccine might offer protection.
To measure the efficacy of one dose of vaccine, Jennifer L. Farrar, MPH, a researcher on the CDC’s Mpox Emergency Response Team, and colleagues analyzed data on 276 people who received a single dose at least 14 days before mpox onset and 6,329 patients with mpox who did not receive the vaccine.
The analysis found that the odds for systemic signs and symptoms of mpox, like fever and chills, also were less among patients who were vaccinated than among those who were unvaccinated.
The researchers said rashes found in the genital and perianal areas among both vaccinated and unvaccinated patients suggest that sexual transmission was common among the study population. They said fewer number of rash locations among patients who were vaccinated suggests mpox rash can also possibly be prevented by vaccination.
“The more limited distribution of rash and reduced severity of illness among persons who had mpox after receiving one Jynneos vaccine dose supports the potential benefit of vaccination on attenuation of disease,” Farrar and colleagues wrote.
“Although infection more than 14 days after receipt of one Jynneos vaccine dose is infrequent, the occurrence of such cases and the unknown duration of protection conferred by one vaccine dose highlights the need for providers and public health officials to encourage completion of the two-dose vaccination series among persons at risk,” they wrote.
References:
- CDC. Mpox: Outbreak cases and data. https://www.cdc.gov/poxvirus/monkeypox/response/2022/index.html. Updated Dec. 28, 2022. Accessed Jan. 4, 2023.
- Farrar J, et al. MMWR Morbid Mortal Wkly Rep. 2023: doi:10.15585/mmwr.mm715152a2
- Payne AB, et al MMWR Morb Mortal Wkly Rep. 2022;doi:10.15585/mmwr.mm7140e3.
Perspective
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Amira A. Roess, PhD, MPH
The MMWR piece presents data that show that even partial mpox vaccination — one dose of a two-dose regimen — may lead to decreased severity of mpox illness and hospitalizations. It concludes that all eligible persons are recommended to complete the two-dose vaccination series.
The MMWR also highlights subtly, and not so subtly, the realities of public and medical health care access in this country — health inequity at every turn and an inadequate public health surveillance system. The real-life implications of this felt by those working in public and medical health care are that we’ll take what we can get — it is a tall order to provide a two-dose vaccine and it is good enough news that partial mpox protection is afforded by one dose.
Among the study population, more white individuals were vaccinated (68.2%) vs. those who were Black (12.4%), and this is a significant difference. The mpox cases that occurred among the small percentage of vaccinated individuals had lower hospitalization rates and symptoms. A few things stand out — we have access to very limited data, which is what we are relying on to make policy decisions, and there is a glaring health equity issue.
The COVID-19 pandemic could have resulted in the development of a robust public health system complete with a representative surveillance system. Such a system could actually mean identifying cases early on and preventing outbreaks, and also identifying inequities at the beginning of a health crisis.
The pandemic also could have resulted in a moment where our country recognizes the importance of meaningful health care coverage for all of its citizens and acts accordingly, following in the footsteps of other high-income countries that provide high-quality health care access and a safety net for its citizens. If the mpox outbreak was the test, we failed. And this reality did not surprise any of us who’ve been working in public health in the U.S. and who have studied health systems in other countries.
Given our lack of a robust public and medical health care system, it has always been difficult to ensure that individuals complete a multiple-dose vaccine regimen, and it has always been difficult to provide follow-up care, especially for those who are under-engaged in health care. Populations that are not engaged in health care include at least two groups. Black and brown populations, particularly those in low-income settings, have poor access to any health care, let alone high-quality health care. Ongoing medical and structural racism stemming from centuries of unethical, but legal, treatment of non-white populations has resulted in distrust of health care and other systems, and this is manifested in lower health care quality indicators among these populations. Also, LGBTQ+ populations have for centuries lived in fear of violence and discrimination, and were also the subject of systematic abuses by medical and other structural systems.
So, when we are facing any health care crisis, these are the populations that our society has systematically set up to be at the bottom of the priority list. In the spring of 2020, those few public and medical health workers who work closely with historically disenfranchised populations called for resources to be allocated specifically toward populations and neighborhoods that were socially vulnerable. It was clear to them that the COVID-19 pandemic would become a disease of the “have-nots.”
But for months, resources to deal with the pandemic went to more affluent and white communities. Tests, vaccines, medical equipment and therapies were systematically made available to the wealthiest first. The COVID-19 vaccine was initially a two-dose vaccine, and health care workers expected that populations historically and currently ignored would not easily be reached. From the beginning, it was impossible to accurately determine which segments of the population were fully vaccinated because of our underfunded public health surveillance system and woefully inadequate electronic medical record system that does not allow a patient to access their complete medical history easily in one place.
The consequences of not knowing who is under-vaccinated is that you cannot create programs to improve vaccination. Similar to mpox, one dose of COVID-19 vaccine was seen to provide sufficient protection against severe disease. Of course, the COVID-19 vaccine story is more complex than this short perspective can relay, but what the reader should immediately see are the parallels between the access and health equity issue of the COVID-19 and mpox vaccines, and the lack of public health surveillance infrastructure.
Because our data systems don’t talk to each other, we continue to use a fraction of the data that should be made available — the data are usually not representative, and come well after the need to make evidence-based decisions.
Nearly 3 years after the start of the COVID-19 pandemic, we are failing the same tests.
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