FDA approves shedding, pustule-inducing ACAM2000 vaccine for Mpox

just like we knew it would

So this happened…

https://x.com/fynnderella1/status/1831049037166055476

From the Emergent BioSolutions press release:

Emergent BioSolutions Inc. (NYSE: EBS) today announced that the U.S. Food and Drug Administration (FDA) has approved the supplemental Biologics License Application (sBLA) for the expansion of the indication for ACAM2000®, (Smallpox and Mpox (Vaccinia) Vaccine, Live) to include prevention of mpox disease in individuals determined to be at high risk for mpox infection. The approval is based on previously available human safety data and data from a well-controlled animal study in which ACAM2000® vaccine was shown to be effective in protecting against mpox virus exposure.

This isn’t a surprise to anyone who’s been paying attention. This is the shedding vaccine that I recently wrote about.

MPox vaccines that shed and other lessons regulatory and public health authorities just won't learn

As stated earlier, the US has a large supply of ACAM2000, which has been approved for smallpox, but “could be made available for use against mpox under an Expanded Access Investigational New Drug (EA-IND) protocol.” We need to be vigilant about this. Here’s why…

From ACAM2000’s package insert:

ACAM2000 is a live vaccinia virus that can be transmitted to persons who have close contact with the vaccinee and the risks in contacts are the same as those stated for vaccinees. (emphasis mine)

What are those risks??

Encephalitis, encephalomyelitis, encephalopathy, progressive vaccinia (vaccinia necrosum), generalized vaccinia, severe vaccinial skin infections, erythema multiforme major (including Stevens-Johnson syndrome) and eczema vaccinatum. Severe disability, permanent neurological sequelae, and/or death may occur. Death of unvaccinated individuals who have contact with vaccinated individuals. [See Warnings and Precautions (5.1)]. • Myocarditis and/or pericarditis, ischemic heart disease and nonischemic, dilated cardiomyopathy [See Warnings and Precautions (5.1)]. • Ocular complications and blindness [See Warnings and Precautions (5.3)].

Inadvertent inoculation at other body sites is the most frequent complication of vaccinia vaccination, usually resulting from autoinoculation of the vaccine virus transferred from the site of vaccination. The most common sites involved are the face, nose, mouth, lips, genitalia and anus. Accidental infection of the eye (ocular vaccinia) may result in ocular complications including, but not limited to, keratitis, corneal scarring and blindness.

Inadvertent inoculation (aka spreading of vaccine virus) is a frequent complication because of how the vaccine “works”.

The primary determinant for an effective immune response in those naïve to vaccine is a major cutaneous reaction… In an individual vaccinated for the first time (primary vaccination), the expected response to vaccination is the development of a major cutaneous reaction (characterized by a pustule) at the site of inoculation. The lesion evolves gradually, with appearance of a papule at the site of vaccination after 2-5 days. The papule becomes vesicular, then pustular, and reaches its maximum size at 8-10 days after vaccination. The pustule dries and forms a scab, which usually separates within 14-21 days, leaving a pitted scar. (See Figure 1) Formation of a major cutaneous reaction by day 6-8 is evidence of a successful ‘take’ and acquisition of protective immunity. An equivocal reaction is any reaction that is not a major reaction, and indicates a non-take (vaccination failure) due to impotent vaccine or inadequate vaccination technique. (emphasis mine)

Looks like Mpox is going to be a thing. Now would be a good time to get informed. Think carefully and know what you’re going to say if you’re offered an Mpox vaccine. Maybe review the playbook…

Maybe it's time to revisit the Mpox tabletop exercise from 2021

If you somehow still decide you want a shot, make sure you know which one you’re getting.