Thread by @ejustin46

𝙎𝙖𝙛𝙚𝙩𝙮, 𝙩𝙤𝙡𝙚𝙧𝙖𝙗𝙞𝙡𝙞𝙩𝙮, 𝙫𝙞𝙧𝙖𝙡 𝙠𝙞𝙣𝙚𝙩𝙞𝙘𝙨, 𝙖𝙣𝙙 𝙞𝙢𝙢𝙪𝙣𝙚 𝙘𝙤𝙧𝙧𝙚𝙡𝙖𝙩𝙚𝙨 𝙤𝙛 𝙥𝙧𝙤𝙩𝙚𝙘𝙩𝙞𝙤𝙣 𝙞𝙣 𝙝𝙚𝙖𝙡𝙩𝙝𝙮, 𝙨𝙚𝙧𝙤𝙥𝙤𝙨𝙞𝙩𝙞𝙫𝙚 𝙐𝙆 𝙖𝙙𝙪𝙡𝙩𝙨 𝙞𝙣𝙤𝙘𝙪𝙡𝙖𝙩𝙚𝙙 𝙬𝙞𝙩𝙝 𝙎𝘼𝙍𝙎-𝘾𝙤𝙑-2
thelancet.com/journals/lanmi…

2) This study investigated a controlled human infection model (CHIM) using SARS-CoV-2 in individuals with pre-existing immunity from prior infection and/or vaccination.
36 volunteers with documented prior SARS-CoV-2 infection were enrolled and given intranasal inoculations ...3

3) ...of increasing doses of SARS-CoV-2, from 1x101 to 1x105 TCID50.
Despite dose escalation, sustained infection was not induced in any volunteers. 5 volunteers (14%) showed transient infection based on PCR-detected virus outside the immediate post-inoculation period.

4) Transiently infected volunteers had significantly lower baseline mucosal and systemic antibody levels against SARS-CoV-2, compared to uninfected volunteers.
Transiently infected volunteers also had significantly lower baseline IFNγ responses ...

5) ...to a CD8+ T cell epitope peptide pool by ELISpot.
39% of volunteers subsequently developed asymptomatic community-acquired omicron infection during follow-up.
The study demonstrated potent protective immunity against homologous re-infection induced ...

6) ...by prior infection, vaccination, or their combination. It was not able to establish a CHIM that reliably induces infection in those with pre-existing immunity.
In summary, this first SARS-CoV-2 CHIM in individuals ...

7) ... with prior immunity showed protection against sustained re-infection but identified some correlates of the weaker transient infection seen in a small number of volunteers. It provided validation of the safety and relevance of SARS-CoV-2 CHIMs.

Thanks for reading 🙏