Monkeypox Outbreak: Weekly Update (September 12, 2022)

Cases of new monkeypox infections continue to decrease in the US and globally. The clinical trial evaluating intradermal delivery of the JYNNEOS vaccine against monkeypox started enrolling participants.

The US passed 20,000 monkeypox cases last week, accounting for more than a third of global cases; however, vaccination coupled with efforts to increase awareness and prevent transmission seem to be curtailing growth in cases.

A downward trend in cases

The World Health Organization (WHO) said on Thursday that while the reported cases of monkeypox in the Americas declined last week, it is still hard to draw firm conclusions about the epidemic in that region.

According to the WHO Director-General Tedros Adhanom Ghebreyesus, some countries in the Americas continue to report increasing numbers of cases. In addition, some countries are likely underreporting due to stigma, discrimination, or a lack of information for those who need it most.

“A downward trend can be the most dangerous time if it opens the door to complacency. The WHO continues to recommend that all countries persist with a tailored combination of public health measures, testing, research, and targeted vaccination, where vaccines are available,” Tedros said during the press briefing.

Trial to evaluate intradermal route

The National Institute of Allergy and Infectious Diseases (NIAID) announced the beginning of a clinical trial evaluating intradermal delivery of the monkeypox vaccine JYNNEOS. The trial will enroll more than 200 adults aged 18 to 50 who have not been vaccinated against smallpox or monkeypox across eight US research sites.

This trial will evaluate whether a reduced dose administered just beneath the top layer of the skin is as effective as the traditional higher-dose subcutaneous injection. Initial results of the trial are expected in early 2023.

The US Food and Drug Administration (FDA) approved the JYNNEOS vaccine in 2019 to protect against smallpox and monkeypox for administration with a series of two subcutaneous injections.

In an effort to stretch the limited supply of the vaccine, last month the FDA allowed vaccine clinics to split the JYNNEOS dose into five for intradermal injection — between the layers of the skin.

Data to support the efficacy of the JYNNEOS vaccine via traditional and intradermal routes are scarce because, so far, only animal testing has been conducted.

HIV prevalent among monkeypox patients

A new study from the Centers for Disease Control and Prevention (CDC) indicates that HIV is prevalent among monkeypox patients. Based on data from eight US jurisdictions provided to the agency, among 1,969 persons diagnosed with monkeypox during May 17 – July 22, HIV prevalence was 38%, and 41% had an STI in the preceding year.

Among people with HIV and monkeypox, 8% were hospitalized, compared to 3% of monkeypox patients without HIV.

Study authors note that consideration should be given to prioritizing persons with HIV infection and STIs for vaccination against monkeypox.