CDC says mpox vaccine performed well, safely
The mpox vaccine worked well at preventing symptoms and shortening the course of the disease formerly known as monkeypox, and it should continue to be used, a federal panel decided Wednesday.
A global outbreak, which arrived in the United States in May of last year, sickened more than 30,000 and killed 32 in the U.S. before mostly petering out. Since early this year, cases in the U.S. have trickled in at no more than a handful a week, though officials at the Centers for Disease Control and Prevention were quick to point out that the outbreak continues.
The vaccine, particularly when given in two doses, performed well and appeared safe, CDC experts told the committee in several hours of testimony.
The 14-member Advisory Committee on Immunization Practices then voted unanimously to support continued use of the vaccine in adults during an mpox outbreak.
The mpox virus is a milder version of the related smallpox. In most people who were infected, the virus caused blistering, which healed over two to four weeks. Some had more serious disease when the poxes were located in sensitive areas, such as the eye.
The most severely affected were those with uncontrolled HIV who also developed mpox, according to a study published Tuesday in The Lancet.
Until last year, mpox had largely been contained to the African continent. It is not known precisely why the virus jumped first to Europe and then the rest of the world in late spring, infecting 86,000 people in 110 countries, killing 92.
More than 1 million doses of the Jynneos vaccine were distributed in the U.S., most of them in the late summer. The Jynneos vaccine is intended to be given as two doses one month apart, although some protection was seen in people who received only one.
h The vaccine appeared to be very
safe, with no problems that hadn’t been expected based on a clinical trial, CDC officials said.
h Short-term side effects from the shots included redness, pain and swelling at the injection site, pain, fatigue, headache and dizziness. There were very few serious events connected to the Jynneos vaccine.
h A small number of vaccinated people suffered myocarditis, a swelling of the heart muscle, after vaccination, but it wasn’t clear whether that occurred more often than in the general public.
h No pregnant people received the vaccine and too little was known about the immune status of people who received the vaccine to determine its safety in pregnancy or among those with immunocompromising conditions or medications.
Vaccine effectiveness varied by study, but one U.S. study found that people who were unvaccinated were seven times more likely to develop mpox than those who received one dose of Jynneos and nearly 10 times more likely than those who received two doses.
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