Link to the University of Pittsburgh Homepage
Link to the University Library System Homepage Link to the Contact Us Form

Seroprevalence following the second wave of pandemic 2009 H1N1 influenza in Pittsburgh, PA, USA

Zimmer, SM and Crevar, CJ and Carter, DM and Stark, JH and Giles, BM and Zimmerman, RK and Ostroff, SM and Lee, BY and Burke, DS and Ross, TM (2010) Seroprevalence following the second wave of pandemic 2009 H1N1 influenza in Pittsburgh, PA, USA. PLoS ONE, 5 (7).

Published Version
Available under License : See the attached license file.

Download (259kB) | Preview
[img] Plain Text (licence)
Available under License : See the attached license file.

Download (1kB)


Background: In April 2009, a new pandemic strain of influenza infected thousands of persons in Mexico and the United States and spread rapidly worldwide. During the ensuing summer months, cases ebbed in the Northern Hemisphere while the Southern Hemisphere experienced a typical influenza season dominated by the novel strain. In the fall, a second wave of pandemic H1N1 swept through the United States, peaking in most parts of the country by mid October and returning to baseline levels by early December. The objective was to determine the seroprevalence of antibodies against the pandemic 2009 H1N1 influenza strain by decade of birth among Pittsburgh-area residents. Methods and Findings: Anonymous blood samples were obtained from clinical laboratories and categorized by decade of birth from 1920-2009. Using hemagglutination-inhibition assays, approximately 100 samples per decade (n = 846) were tested from blood samples drawn on hospital and clinic patients in mid-November and early December 2009. Age specific seroprevalences against pandemic H1N1 (A/California/7/2009) were measured and compared to seroprevalences against H1N1 strains that had previously circulated in the population in 2007, 1957, and 1918. (A/Brisbane/59/2007, A/Denver/1/ 1957, and A/South Carolina/1/1918). Stored serum samples from healthy, young adults from 2008 were used as a control group (n = 100). Seroprevalences against pandemic 2009 H1N1 influenza varied by age group, with children age 10-19 years having the highest seroprevalence (45%), and persons age 70-79 years having the lowest (5%). The baseline seroprevalence among control samples from 18-24 year-olds was 6%. Overall seroprevalence against pandemic H1N1 across all age groups was approximately 21%. Conclusions: After the peak of the second wave of 2009 H1N1, HAI seroprevalence results suggest that 21% of persons in the Pittsburgh area had become infected and developed immunity. Extrapolating to the entire US population, we estimate that at least 63 million persons became infected in 2009. As was observed among clinical cases, this sero-epidemiological study revealed highest infection rates among school-age children. © 2010 Zimmer et al.


Social Networking:
Share |


Item Type: Article
Status: Published
CreatorsEmailPitt UsernameORCID
Zimmer, SMzimmersm@pitt.eduZIMMERSM
Crevar, CJ
Carter, DM
Stark, JH
Giles, BM
Zimmerman, RKzimmer@pitt.eduZIMMER0000-0001-5941-6092
Ostroff, SM
Lee, BYbyl1@pitt.eduBYL1
Burke, DSdonburke@pitt.eduDONBURKE
Ross, TM
ContributionContributors NameEmailPitt UsernameORCID
Centers: Other Centers, Institutes, Offices, or Units > Center for Vaccine Research
Date: 14 July 2010
Date Type: Publication
Journal or Publication Title: PLoS ONE
Volume: 5
Number: 7
DOI or Unique Handle: 10.1371/journal.pone.0011601
Refereed: Yes
MeSH Headings: Adult; Hemagglutinins--chemistry; Hemagglutinins--classification; Hemagglutinins--genetics; Humans; Influenza A Virus, H1N1 Subtype--pathogenicity; Influenza, Human--blood; Influenza, Human--epidemiology; Pennsylvania--epidemiology; Phylogeny; Seroepidemiologic Studies; United States--epidemiology; Young Adult
Other ID: NLM PMC2904390
PubMed Central ID: PMC2904390
PubMed ID: 20644650
Date Deposited: 15 Aug 2012 18:19
Last Modified: 30 Jan 2024 22:55


Monthly Views for the past 3 years

Plum Analytics

Actions (login required)

View Item View Item