Andrew Lover Profile picture
Assistant Professor, Epidemiology @UMassSPHHS Infectious disease epi & surveillance • Global/public health (all tweets & views my own) https://t.co/Y7DyXNbjPn

May 23, 2022, 15 tweets

▶️ 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

▶️ For most of a decade, there was a large-scale clinical-surveillance study where data were collected from approx.400 #monkeypox cases across West and Central Africa.
4/n

▶️ And what was learned from all these #monkeypox 𝙛𝙞𝙚𝙡𝙙 𝙨𝙩𝙪𝙙𝙞𝙚𝙨 ?? (details below)
Note: all Central African clade:
1. Most infections occurred in sporadic clusters.
2. Serial interval (DRC) was 7-23 days.
3. 31.5% (of 210 cases, DRC) appeared to be H-to-H

5/n

▶️ And what was learned from all these #monkeypox 𝙛𝙞𝙚𝙡𝙙 𝙨𝙩𝙪𝙙𝙞𝙚𝙨 ?? (cont; details below).

4.90% were in small villages, 10% medium (1k-5k pop), very few in larger towns.
5. Subclinical cases were not uncommon in unvaccinated pops (DRC, est. at 18%).
6/n

1. Many infections occurred in sporadic clusters, suggesting a "spillover" with limited subsequent human-to-human transmission.

7/n

2. Serial interval (DRC) was 7-23 days.

8/n

3. 31.5% (of 210 cases, DRC) appeared to be H-to-Human

9/n

89% were in small villages, 10% medium (1k-5k pop), very few in larger towns.

10/n

5. Subclinical cases occurred in unvaccinated pops (DRC, est. at 18%).

11/n

▶️▶️ These findings are largely consistent with 2018-2019 outbreak in Nigeria (same as currently circulating strain), with the exception of rural-urban gradient.

12/n

▶️▶️ What does this all this mean for the current #monkeypox situation?

▶️ Very mild/subclinical/(asymptomatic) cases should be expected (but risk of onward transmission unknown).

Data from: @BNODesk
13/n

▶️ Human-to-human transmission 𝙬𝙞𝙡𝙡 occur.
▶️ We have essentially no understanding of transmission in modern (unvaccinated) and hyper-mobile populations.
▶️▶️ Given these major gaps: we should be proactive, err on the side of caution, and then be pleasantly surprised.
14/n

High-quality and indexed scan of WHO book here:
biotech.law.lsu.edu/blaw/bt/smallp…

15/n (end).

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