▶️ Extensive discussions about potential protection from #monkeypox from pre-1980 smallpox (vaccinia) vaccinations.
▶️ What do we actually know, and
▶️ how well do we know it?
a thread. 1/n
Four main issues:
A. How long did vaccines protect against smallpox?
B. How often was/is 𝙧𝙚𝙫𝙖𝙘𝙘𝙞𝙣𝙖𝙩𝙞𝙤𝙣 recommended?
C. How common were smallpox infections after 𝙧𝙚𝙫𝙖𝙘𝙘𝙞𝙣𝙖𝙩𝙞𝙤𝙣 ?
D. How well does smallpox vax protect against #monkeypox?
2/n
A. Length of protection
▶️ From current ACIP guide, no definitive evidence, but epi studies suggest strong protection for <5 years, with some protection out to 10+ years.
3/n
B. Revaccination
1965 guidance says 5-year intervals are necessary based on epi data.
▶️▶️ Current guidelines, 3-year intervals, especially if working with replicating/virulent orthopoxviruses, including #monkeypox.
(note: these are 𝙫𝙚𝙧𝙮 conservative for safety)
5/n
B. revaccination
How long do titres remain high, and what levels confer protection from infection?
Long-term followup, 🇮🇱 military.
▶️ "The protective significance of the above titre is unknown."
▶️ Primary + two-revacciantions "probably" sufficient pubmed.ncbi.nlm.nih.gov/2155973/ 6/n
1. We cannot assume any long-term #monkeypox protection from historical smallpox vaccination. It's likely limited. 2. While JYNNEOS may have good efficacy, we cannot assume it, and we have no data on 𝙚𝙛𝙛𝙚𝙘𝙩𝙞𝙫𝙚𝙣𝙚𝙨𝙨.
11/n
▶️▶️ What are next steps?
▶️ Plan for limited effectiveness against #monkeypox, and implement broader health programming
-----> there are no "magic bullets"
▶️ Uptake for post-exposure vax in UK was very low
▶️ Understanding this is essential!
▶️ How 𝙢𝙞𝙜𝙝𝙩 the current #monkeypox situation progress in non-endemic areas?
A thread,
1/n
▶️ There are 3 likely #monkeypox scenarios IMHO (from most to least likely)
A. Semi-rapid mitigation and elimination.
B. Low-level endemicity.
C. Major expansion, mortality and a concurrent pandemic.
▶️ Things the scientific community may have largely forgotten about regarding #monkeypox.
A thread,
1/n
▶️ In 1988 DA Henderson and colleagues at WHO published the smallpox eradication "redbook" (1473 pages, 3.1 kg!).
𝙒𝙝𝙮?? Because they were concerned their hard-won knowledge would evaporate.
▶️ And guess what?
▶️ There's a whole chapter on #monkeypox ! 2/n
But 𝙒𝙝𝙮?? Because monkeypox was a major barrier to eradication.
▶️ It was clinically indistinguishable from mild(er) smallpox, so every single case had to be confirmed as NOT smallpox for eradication certification. 3/n
In 2014, reports of "peculiar" Guinea Worm infections in dogs in one river basin in Chad.
▶️ Initial explanation: unusual pop of dogs in isolated areas feeding on fish; risk to humans was "sporadic and incidental."
🚨 Reality: many areas in Chad; plus baboons in Ethiopia. 2/n
In 2001, report of circulating-vaccine derived polio on Hispaniola .
▶️ Initial explanation: very rare occurrence in low vaccine settings.
🚨 Reality: Currently (a or 𝙩𝙝𝙚) major challenge for the entire polio eradication campaign. 3/n
Simple practical guidance on steps you can take
▶️▶️ right now
▶️▶️ to prepare yourself, your family and within your community
▶️▶️ in the event of widespread #COVID19 transmission.