#18,314
Yesterday the CDC released an updated HAN (Health Alert Network), primarily geared for clinicians, on how to advise patients who may be at risk of contracting Mpox, or those who may be planning to travel to countries where the virus is currently circulating.
Due to its length, I've only posted the summary, and a brief excerpt. Follow the link to read the full update. I'll have a brief postscript after the break.
Prevention Strategies for Mpox, including Vaccinating People at Risk via Sexual Exposure, for U.S. Travelers Visiting Countries with Clade I Mpox Outbreaks
Distributed via the CDC Health Alert Network
September 23, 2024, 12:45 PM ET
CDCHAN-00516
Summary
The Centers for Disease Control and Prevention (CDC) is issuing this Health Alert Network (HAN) Health Update to provide additional information about the ongoing outbreak of clade I monkeypox virus (MPXV), the virus that causes mpox, in Central and Eastern Africa.This report is an update to HAN Health Advisory 501 issued in December 2023 and HAN Heath Update 513 in August 2024. MPXV transmission in countries where the virus is endemic is typically via exposure to infected wildlife with subsequent person-to-person spread via close contact (including intimate or sexual contact) with a person with mpox, or direct contact with their respiratory secretions (e.g., snot, mucus) or contaminated objects (e.g., bedding).During the global clade II outbreak, human-to-human transmission of mpox has been predominantly spreading through sexual contact. During 2024, the Democratic Republic of the Congo (DRC) has reported >21,000 suspected clade I mpox cases, its largest annual number on record. Although the proportion of people impacted in DRC (population >99 million) is relatively low, cases are more widespread than in any previously reported DRC outbreak. Clade Ia mpox cases are impacting the western part of DRC (particularly the rural Équateur Province).No cases of clade Ia mpox have been reported outside Central African countries where clade Ia MPXV is endemic. Clade Ib mpox cases are impacting the eastern part of DRC and have been spread through regional travel. Early data indicate that a large proportion of clade Ib mpox cases among adults has been associated with sexual contact, including via ongoing transmission believed to be occurring in some countries where the virus is not normally found.Travelers to DRC or other countries with sustained spread of clade I mpox, regardless of sexual orientation or gender identity, should be made aware of activities associated with cases and should be vaccinated with two doses of JYNNEOS if they anticipate certain sexual exposures while traveling. Active monitoring for mpox continues to occur in the United States.Although the United States continues to be affected by an ongoing global outbreak of clade II mpox that began in 2022, no domestic cases of clade I mpox have been identified in the United States at this time. Continue to follow CDC’s current vaccine guidance to prevent clade II MPXV infection, which continues to circulate in the United States, and will also help protect against clade I MPXV.
(SNIP)
In February 2023, the CDC Advisory Committee on Immunization Practices (ACIP) recommended a JYNNEOS vaccine series, with two doses administered 28 days apart, for people aged 18 years and older at risk of mpox during an mpox outbreak. This ACIP recommendation, which has been adopted by the CDC Director and is now official, leaves the determination of whether there is an mpox outbreak and the populations impacted to public health authorities.
CDC has determined that ongoing human-to-human transmission of clade I MPXV in Central and East Africa is an outbreak and, in addition to general prevention strategies, recommends a JYNNEOS 2-dose vaccine series for persons at risk for mpox via sexual exposure during travel to a country with ongoing human-to-human transmission.
Although the JYNNEOS vaccine is not 100% effective in preventing infection, and we've seen at least 3 studies suggesting its effectiveness may wane over time (see here, here, and here), it is still the most effective pharmaceutical option available, and it is understandable why the CDC would seek to promote it to at-risk individuals.
The danger, of course, is that recipients erroneously believe that once vaccinated, they are completely protected, and decide not to follow the other prevention recommendations from the CDC.
Three weeks ago, in EID Journal Dispatch: Mpox Epidemiology and Vaccine Effectiveness, England, 2023 we saw a report from the UK which found that nearly half of new community acquired mpox cases in 2023 were in vaccinated individuals. They note:
Nearly half of outbreak case-patients in 2023 were vaccinated, and there were more cases among those who had received 2 doses of MVA-BN vaccine than among those who had received 1 dose.This unexpected result, they suspect, may have more to do with the risk behavior of some who may feel fully `protected' by two-doses of the vaccine, than the vaccine itself. Add in a possible gradual loss of protection over time, and you have an increased potential for breakthrough infections.
