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Article: Estimating infection attack rates and severity in real time during an influenza pandemic: Analysis of serial cross-sectional serologic surveillance data
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TitleEstimating infection attack rates and severity in real time during an influenza pandemic: Analysis of serial cross-sectional serologic surveillance data
 
AuthorsWu, JT1
Ho, A1
Ma, ESK1
Lee, CK2
Chu, DKW1
Ho, PL1
Hung, IFN1
Ho, LM1
Lin, CK2
Tsang, T5
Lo, SV2 3
Lau, YL1
Leung, GM3
Cowling, BJ1
Peiris, JSM1 4
 
Keywords2009 h1n1 influenza
Controlled study
Cross-sectional study
Disease transmission
Epidemic
 
Issue Date2011
 
PublisherPublic Library of Science. The Journal's web site is located at http://medicine.plosjournals.org/perlserv/?request=index-html&issn=1549-1676
 
CitationPlos Medicine, 2011, v. 8 n. 10 [How to Cite?]
DOI: http://dx.doi.org/10.1371/journal.pmed.1001103
 
AbstractBackground: 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 emerging pandemic. Sero-surveillance for pandemics should be considered. Please see later in the article for the Editors' Summary. © 2011 Wu et al.
 
ISSN1549-1277
2012 SCImago Journal Rankings: 4.105
 
DOIhttp://dx.doi.org/10.1371/journal.pmed.1001103
 
PubMed Central IDPMC3186812
 
ISI Accession Number IDWOS:000296552400004
Funding AgencyGrant Number
Food and Health Bureau, Government of the Hong Kong SARPHE-20
10090272
Hong Kong University Grants CommitteeAoE/M-12/06
Harvard Center for Communicable Disease Dynamics from the US National Institutes of Health Models of Infectious Disease1 U54 GM088558
EMPERIE (EU)223498
National Institute of Allergy and Infectious Diseases, NIHHHSN266200700005C
N01-AI-70005
MedImmune Inc.
Funding Information:

This project was supported by the Research Fund for the Control of Infectious Disease, Food and Health Bureau, Government of the Hong Kong SAR (grants PHE-20 and 10090272), the Area of Excellence Scheme of the Hong Kong University Grants Committee (grant AoE/M-12/06), the Harvard Center for Communicable Disease Dynamics from the US National Institutes of Health Models of Infectious Disease Agent Study program (grant 1 U54 GM088558), EMPERIE (EU FP7 grant 223498), and the National Institute of Allergy and Infectious Diseases, NIH (contract HHSN266200700005C; ADB No. N01-AI-70005). The funding bodies had no role in study design, data collection and analysis, preparation of the manuscript, or the decision to publish.

 
ReferencesReferences in Scopus
 
GrantsA 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
 
DC FieldValue
dc.contributor.authorWu, JT
 
dc.contributor.authorHo, A
 
dc.contributor.authorMa, ESK
 
dc.contributor.authorLee, CK
 
dc.contributor.authorChu, DKW
 
dc.contributor.authorHo, PL
 
dc.contributor.authorHung, IFN
 
dc.contributor.authorHo, LM
 
dc.contributor.authorLin, CK
 
dc.contributor.authorTsang, T
 
dc.contributor.authorLo, SV
 
dc.contributor.authorLau, YL
 
dc.contributor.authorLeung, GM
 
dc.contributor.authorCowling, BJ
 
dc.contributor.authorPeiris, JSM
 
dc.date.accessioned2011-12-21T08:54:15Z
 
dc.date.available2011-12-21T08:54:15Z
 
dc.date.issued2011
 
dc.description.abstractBackground: 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 emerging pandemic. Sero-surveillance for pandemics should be considered. Please see later in the article for the Editors' Summary. © 2011 Wu et al.
 
dc.description.naturepublished_or_final_version
 
dc.identifier.citationPlos Medicine, 2011, v. 8 n. 10 [How to Cite?]
DOI: http://dx.doi.org/10.1371/journal.pmed.1001103
 
dc.identifier.citeulike9885685
 
dc.identifier.doihttp://dx.doi.org/10.1371/journal.pmed.1001103
 
dc.identifier.epage11
 
dc.identifier.hkuros198000
 
dc.identifier.isiWOS:000296552400004
Funding AgencyGrant Number
Food and Health Bureau, Government of the Hong Kong SARPHE-20
10090272
Hong Kong University Grants CommitteeAoE/M-12/06
Harvard Center for Communicable Disease Dynamics from the US National Institutes of Health Models of Infectious Disease1 U54 GM088558
EMPERIE (EU)223498
National Institute of Allergy and Infectious Diseases, NIHHHSN266200700005C
N01-AI-70005
MedImmune Inc.
Funding Information:

This project was supported by the Research Fund for the Control of Infectious Disease, Food and Health Bureau, Government of the Hong Kong SAR (grants PHE-20 and 10090272), the Area of Excellence Scheme of the Hong Kong University Grants Committee (grant AoE/M-12/06), the Harvard Center for Communicable Disease Dynamics from the US National Institutes of Health Models of Infectious Disease Agent Study program (grant 1 U54 GM088558), EMPERIE (EU FP7 grant 223498), and the National Institute of Allergy and Infectious Diseases, NIH (contract HHSN266200700005C; ADB No. N01-AI-70005). The funding bodies had no role in study design, data collection and analysis, preparation of the manuscript, or the decision to publish.

 
dc.identifier.issn1549-1277
2012 SCImago Journal Rankings: 4.105
 
dc.identifier.issue10
 
dc.identifier.pmcidPMC3186812
 
dc.identifier.pmid21990967
 
dc.identifier.scopuseid_2-s2.0-80055051035
 
dc.identifier.spage1
 
dc.identifier.urihttp://hdl.handle.net/10722/143768
 
dc.identifier.volume8
 
dc.languageeng
 
dc.publisherPublic Library of Science. The Journal's web site is located at http://medicine.plosjournals.org/perlserv/?request=index-html&issn=1549-1676
 
dc.publisher.placeUnited States
 
dc.relation.ispartofPLoS Medicine
 
dc.relation.projectA 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
 
dc.relation.projectControl of Pandemic and Inter-pandemic Influenza
 
dc.relation.projectA 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
 
dc.relation.referencesReferences in Scopus
 
dc.rightsCreative Commons: Attribution 3.0 Hong Kong License
 
dc.subject2009 h1n1 influenza
 
dc.subjectControlled study
 
dc.subjectCross-sectional study
 
dc.subjectDisease transmission
 
dc.subjectEpidemic
 
dc.titleEstimating infection attack rates and severity in real time during an influenza pandemic: Analysis of serial cross-sectional serologic surveillance data
 
dc.typeArticle
 
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Author Affiliations
  1. The University of Hong Kong Li Ka Shing Faculty of Medicine
  2. Hong Kong Hospital Authority
  3. Food and Health Bureau
  4. HKU-Pasteur Research Centre
  5. Centre for Health Protection