A Multicenter, Controlled Human Infection Study of Influenza A(H1N1)pdm09 in Healthy Adults.
J Infect Dis
; 228(3): 287-298, 2023 08 11.
Article
in En
| MEDLINE
| ID: mdl-36702771
ABSTRACT
BACKGROUND:
We evaluated the associations between baseline influenza virus-specific hemagglutination inhibition (HAI) and microneutralization (MN) titers and subsequent symptomatic influenza virus infection in a controlled human infection study.METHODS:
We inoculated unvaccinated healthy adults aged 18-49 years with an influenza A/California/04/2009/H1N1pdm-like virus (NCT04044352). We collected serial safety labs, serum for HAI and MN, and nasopharyngeal swabs for reverse-transcription polymerase chain reaction (RT-PCR) testing. Analyses used the putative seroprotective titer of ≥40 for HAI and MN. The primary clinical outcome was mild-to-moderate influenza disease (MMID), defined as ≥1 postchallenge positive qualitative RT-PCR test with a qualifying symptom/clinical finding.RESULTS:
Of 76 participants given influenza virus challenge, 54 (71.1%) experienced MMID. Clinical illness was generally very mild. MMID attack rates among participants with baseline titers ≥40 by HAI and MN were 64.9% and 67.9%, respectively, while MMID attack rates among participants with baseline titers <40 by HAI and MN were 76.9% and 78.3%, respectively. The estimated odds of developing MMID decreased by 19% (odds ratio, 0.81 [95% confidence interval, .62-1.06]; P = .126) for every 2-fold increase in baseline HAI. There were no significant adverse events.CONCLUSIONS:
We achieved a 71.1% attack rate of MMID. High baseline HAI and MN were associated with protection from illness. Clinical Trials Registration. NCT04044352.Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Influenza Vaccines
/
Influenza, Human
/
Influenza A Virus, H1N1 Subtype
Type of study:
Clinical_trials
/
Qualitative_research
Limits:
Adult
/
Humans
Language:
En
Journal:
J Infect Dis
Year:
2023
Type:
Article