Two doses of the Jynneos monkeypox vaccine, which was developed as a smallpox vaccine, generate relatively low antibody levels with poor capacity to neutralize the virus, according to findings published Aug. 31 in the preprint server medRxiv.
Researchers said the early findings raise questions about how well vaccinated individuals are protected. The findings also suggest the dose-sparing strategy — which is being used in the U.S. to stretch vaccine supplies — may reduce virus immunity.
"Studies following vaccinated individuals are necessary to further assess vaccine efficacy in risk populations and determine correlates of protection for this emerging pathogen," researchers said.
Three more updates:
1. New cases have fallen 40 percent since early August, according to an analysis of CDC data by NBC News. The nation's seven-day average for new cases fell from 465 on Aug. 10 to 281 on Aug. 31. The decrease is largely driven by falling case counts in large cities like New York City, Chicago and Los Angeles. Since the start of the outbreak in May, nearly 20,000 cases have been confirmed in the U.S. as of Sept. 2.
2. Monkeypox may lead to heart muscle inflammation, a case study from a patient in Portugal suggests. Researchers said a patient presented to the emergency room reporting chest tightness about one week after first developing monkeypox symptoms. Cardiac magnetic resonance mapping was used to confirm the myocarditis, or heart muscle inflammation, diagnosis. The patient fully recovered and was discharged one week later.
3. There have been at least 31 cases among children in the U.S., according to state data compiled by ABC News. The pediatric cases span 11 states, including Texas, where nine pediatric cases have been reported.