Atlanta—With the first confirmed case of monkeypox occurring in Massachusetts in mid-May, the situation has worsened quickly. Public health officials reported that by late July, nearly 3,500 cases had been reported in 45 states, the District of Columbia, and Puerto Rico.

The CDC advised that the cases include those who tested positive for either monkeypox virus or orthopoxvirus as described in the case definition.

The CDC reports that the median age of patients is 35 years (range 18-76), and—of the 1,383 patients with information on sex assigned at birth—99.1% were assigned male sex, with only 13 assigned female sex. Of the 870 patients with information on gender identity, one self-reported as a transgender male. Nearly all (99%) of patients reported male-to-male sexual contact.

As for known race/ethnicity, 38% of patients with known race/ethnicity are white/non-Hispanic, 26% are black, and 32% are Hispanic (of any race). The CDC reported, however, that data are missing for a large number of cases.

Public health officials noted that two vaccines may be used for the prevention of the monkeypox virus infection. One is Jynneos (also known as Imvamune or Imvanex), licensed by the FDA for the prevention of monkeypox virus infection. The other is ACAM2000, licensed by the FDA for use against smallpox and made available for use against monkeypox under an expanded-access investigational new drug application.

Supplies of Jynneos are currently limited in the U.S., but more doses are expected in the coming weeks or months, according to the CDC. While the supply of ACAM2000 is more ample, the vaccine should not be used in people who have certain health conditions, such as a weakened immune system, skin conditions like eczema or other exfoliative skin conditions, or pregnancy.

The CDC pointed out that no data are available yet on the effectiveness of these vaccines in the current outbreak. It did state, however, that the full immune response takes 14 days after the second dose of Jynneos and 4 weeks after the ACAM2000 dose.

It urges recipients to continue to take steps to protect themselves from infection by avoiding close, skin-to-skin contact, including intimate contact with someone who has monkeypox.

In a recent guidance, the CDC calls for standard postexposure prophylaxis for monkeypox, so that those exposed to monkeypox should be vaccinated. That should occur within 4 days from the date of exposure for the best chance to prevent onset of the disease, it added.

If given after that time but within 14 days after the date of exposure, vaccination might reduce the symptoms of the disease but not necessarily prevent infection. “Benefits may still outweigh risks when giving vaccine more than 14 days after exposure in some clinical situations (e.g., high-risk exposure in a person at high risk for severe disease, such as severe immune compromise),” according to the CDC update. “Vaccination given after the onset of signs or symptoms of monkeypox is not expected to provide benefit.”

The guidance goes on to advise that Jynneos doses should be prioritized for those people who are at risk for serious adverse events with ACAM2000 or severe disease from monkeypox, such as those with HIV or other immunocompromising conditions.

While two doses of Jynneos are required—as this is the only FDA-approved dosing regimen—exceptions exist. “In the context of the current monkeypox outbreak, and while the supply of Jynenos vaccine is limited: A person who is diagnosed with Monkeypox virus infection after their first dose of Jynneos is not recommended to receive the second dose at this time, because monkeypox virus infection likely confers additional immune protection,” the CDC stated.

It adds that a person who would be eligible for vaccination but has been diagnosed with monkeypox virus infection during this outbreak is not recommended to be vaccinated at this time, because monkeypox virus infection likely confers immune protection.

On the other hand, an immunocompromised person who is diagnosed with monkeypox virus infection after their first dose of Jynneos may be eligible to receive the second dose on a case-by-case, shared decision–making basis based on the clinical judgment of the healthcare provider.

The content contained in this article is for informational purposes only. The content is not intended to be a substitute for professional advice. Reliance on any information provided in this article is solely at your own risk.

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