| Title: |
Estimating infection attack rates and severity in real time during an influenza pandemic: Analysis of serial cross-sectional serologic surveillance data |
| Authors: |
Wu, JT; Ho, A; Ma, ESK; Lee, CK; Chu, DKW; Ho, PL; Hung, IFN; Ho, LM; Lin, CK; Tsang, T; Lo, SV; Lau, YL; Leung, GM; Cowling, BJ; Peiris, JSM |
| Publisher Information: |
//medicine.plosjournals.org/perlserv/?request=index-html&issn=1549-1676; United States |
| Publication Year: |
2011 |
| Collection: |
University of Hong Kong: HKU Scholars Hub |
| Description: |
Background: In an emerging influenza pandemic, estimating severity (the probability of a severe outcome, such as hospitalization, if infected) is a public health priority. As many influenza infections are subclinical, sero-surveillance is needed to allow reliable real-time estimates of infection attack rate (IAR) and severity. Methods and Findings: We tested 14,766 sera collected during the first wave of the 2009 pandemic in Hong Kong using viral microneutralization. We estimated IAR and infection-hospitalization probability (IHP) from the serial cross-sectional serologic data and hospitalization data. Had our serologic data been available weekly in real time, we would have obtained reliable IHP estimates 1 wk after, 1-2 wk before, and 3 wk after epidemic peak for individuals aged 5-14 y, 15-29 y, and 30-59 y. The ratio of IAR to pre-existing seroprevalence, which decreased with age, was a major determinant for the timeliness of reliable estimates. If we began sero-surveillance 3 wk after community transmission was confirmed, with 150, 350, and 500 specimens per week for individuals aged 5-14 y, 15-19 y, and 20-29 y, respectively, we would have obtained reliable IHP estimates for these age groups 4 wk before the peak. For 30-59 y olds, even 800 specimens per week would not have generated reliable estimates until the peak because the ratio of IAR to pre-existing seroprevalence for this age group was low. The performance of serial cross-sectional sero-surveillance substantially deteriorates if test specificity is not near 100% or pre-existing seroprevalence is not near zero. These potential limitations could be mitigated by choosing a higher titer cutoff for seropositivity. If the epidemic doubling time is longer than 6 d, then serial cross-sectional sero-surveillance with 300 specimens per week would yield reliable estimates when IAR reaches around 6%-10%. Conclusions: Serial cross-sectional serologic data together with clinical surveillance data can allow reliable real-time estimates of IAR and severity in an ... |
| Document Type: |
article in journal/newspaper |
| Language: |
English |
| Relation: |
PLoS Medicine; A longitudinal study of infection attack rates among hospital outpatients in Hong Kong during the epidemic of the human swine influenza A/H1N1 virus in 2009 by tracking temporal changes in age-specific seroprevalence rates; Control of Pandemic and Inter-pandemic Influenza; A detailed longitudinal study of infection attack rates among healthy adults in Hong Kong during the epidemic of the human swine influenza A/H1N1 virus in 2009; http://www.scopus.com/mlt/select.url?eid=2-s2.0-80055051035&selection=ref&src=s&origin=recordpage; PLoS Medicine, 2011, v. 8 n. 10, article no. e1001103; 9885685; article no. e1001103; 198000; WOS:000296552400004; 10; PMC3186812; https://hub.hku.hk/handle/10722/143768 |
| DOI: |
10.1371/journal.pmed.1001103 |
| Availability: |
https://hub.hku.hk/handle/10722/143768; https://doi.org/10.1371/journal.pmed.1001103 |
| Rights: |
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License. |
| Accession Number: |
edsbas.FF452ED1 |
| Database: |
BASE |