1
|
Rosu ME, Lexmond P, Bestebroer TM, Hauser BM, Smith DJ, Herfst S, Fouchier RAM. Substitutions near the HA receptor binding site explain the origin and major antigenic change of the B/Victoria and B/Yamagata lineages. Proc Natl Acad Sci U S A 2022; 119:e2211616119. [PMID: 36215486 PMCID: PMC9586307 DOI: 10.1073/pnas.2211616119] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 09/13/2022] [Indexed: 11/18/2022] Open
Abstract
Influenza B virus primarily infects humans, causing seasonal epidemics globally. Two antigenic variants-Victoria-like and Yamagata-like-were detected in the 1980s, of which the molecular basis of emergence is still incompletely understood. Here, the antigenic properties of a unique collection of historical virus isolates, sampled from 1962 to 2000 and passaged exclusively in mammalian cells to preserve antigenic properties, were determined with the hemagglutination inhibition assay and an antigenic map was built to quantify and visualize the divergence of the lineages. The antigenic map revealed only three distinct antigenic clusters-Early, Victoria, and Yamagata-with relatively little antigenic diversity in each cluster until 2000. Viruses with Victoria-like antigenic properties emerged around 1972 and diversified subsequently into two genetic lineages. Viruses with Yamagata-like antigenic properties evolved from one lineage and became clearly antigenically distinct from the Victoria-like viruses around 1988. Recombinant mutant viruses were tested to show that insertions and deletions (indels), as observed frequently in influenza B virus hemagglutinin, had little effect on antigenic properties. In contrast, amino-acid substitutions at positions 148, 149, 150, and 203, adjacent to the hemagglutinin receptor binding site, determined the main antigenic differences between the Early, Victoria-like, and Yamagata-like viruses. Surprisingly, substitutions at two of the four positions reverted in recent viruses of the Victoria lineage, resulting in antigenic properties similar to viruses circulating ∼50 y earlier. These data shed light on the antigenic diversification of influenza viruses and suggest there may be limits to the antigenic evolution of influenza B virus.
Collapse
Affiliation(s)
- Miruna E. Rosu
- Department of Viroscience, Erasmus Medical Centre, Rotterdam 3015 CE, The Netherlands
| | - Pascal Lexmond
- Department of Viroscience, Erasmus Medical Centre, Rotterdam 3015 CE, The Netherlands
| | - Theo M. Bestebroer
- Department of Viroscience, Erasmus Medical Centre, Rotterdam 3015 CE, The Netherlands
| | - Blake M. Hauser
- Center for Pathogen Evolution, Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK
| | - Derek J. Smith
- Center for Pathogen Evolution, Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK
| | - Sander Herfst
- Department of Viroscience, Erasmus Medical Centre, Rotterdam 3015 CE, The Netherlands
| | - Ron A. M. Fouchier
- Department of Viroscience, Erasmus Medical Centre, Rotterdam 3015 CE, The Netherlands
| |
Collapse
|
2
|
Gravel C, Muralidharan A, Duran A, Zetner A, Pfeifle A, Zhang W, Hashem A, Tamming L, Farnsworth A, Loemba H, Chen W, Krammer F, Safronetz D, Cao J, Wang L, Sauve S, Rosu-Myles M, Van Domselaar G, Li X. Synthetic vaccine affords full protection to mice against lethal challenge of influenza B virus of both genetic lineages. iScience 2021; 24:103328. [PMID: 34805790 PMCID: PMC8586812 DOI: 10.1016/j.isci.2021.103328] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 09/21/2021] [Accepted: 10/19/2021] [Indexed: 01/09/2023] Open
Abstract
A quarter of all seasonal influenza cases are caused by type B influenza virus (IBV) that also dominates periodically. Here, we investigated a recombinant adenovirus vaccine carrying a synthetic HA2 representing the consensus sequence of all IBV hemagglutinins. The vaccine fully protected mice from lethal challenges by IBV of both genetic lineages, demonstrating its breadth of protection. The protection was not mediated by neutralizing antibodies but robust antibody-dependent cellular cytotoxicity and cell-mediated immune responses. Complete protection of the animals required the entire codon-optimized HA2 sequence that elicited a balanced immune response, whereas truncated vaccines without either the fusion peptide or the transmembrane domain reduced the efficacy of protection. Finally, the vaccines did not demonstrate any sign of disease exacerbation following lung pathology and morbidity monitoring. Collectively, these data suggest that it could be worth further exploring this prototype universal vaccine because of its considerable efficacy, safety, and breadth of protection.
Collapse
Affiliation(s)
- Caroline Gravel
- Centre for Biologics Evaluation, Biologic and Radiopharmaceutical Drugs Directorate, HPFB, Health Canada and WHO Collaborating Center for Standardization and Evaluation of Biologicals, Ottawa, ON, Canada
| | - Abenaya Muralidharan
- Centre for Biologics Evaluation, Biologic and Radiopharmaceutical Drugs Directorate, HPFB, Health Canada and WHO Collaborating Center for Standardization and Evaluation of Biologicals, Ottawa, ON, Canada
| | - Amparo Duran
- Centre for Biologics Evaluation, Biologic and Radiopharmaceutical Drugs Directorate, HPFB, Health Canada and WHO Collaborating Center for Standardization and Evaluation of Biologicals, Ottawa, ON, Canada
| | - Adrian Zetner
- National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB, Canada
| | - Annabelle Pfeifle
- Centre for Biologics Evaluation, Biologic and Radiopharmaceutical Drugs Directorate, HPFB, Health Canada and WHO Collaborating Center for Standardization and Evaluation of Biologicals, Ottawa, ON, Canada.,Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Wanyue Zhang
- Centre for Biologics Evaluation, Biologic and Radiopharmaceutical Drugs Directorate, HPFB, Health Canada and WHO Collaborating Center for Standardization and Evaluation of Biologicals, Ottawa, ON, Canada.,Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Anwar Hashem
- Immunotherapy Unit, Department of Medical Microbiology and Parasitology, Faculty of Medicine and Vaccines, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Levi Tamming
- Centre for Biologics Evaluation, Biologic and Radiopharmaceutical Drugs Directorate, HPFB, Health Canada and WHO Collaborating Center for Standardization and Evaluation of Biologicals, Ottawa, ON, Canada.,Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Aaron Farnsworth
- Centre for Biologics Evaluation, Biologic and Radiopharmaceutical Drugs Directorate, HPFB, Health Canada and WHO Collaborating Center for Standardization and Evaluation of Biologicals, Ottawa, ON, Canada
| | - Hugues Loemba
- Montfort Hospital and Faculty of Medicine, University of Ottawa, Ottawa, On, Canada
| | - Wangxue Chen
- Human Health Therapeutics Research Center, National Research Council of Canada, Ottawa, ON, Canada
| | - Florian Krammer
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - David Safronetz
- National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB, Canada
| | - Jingxin Cao
- National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB, Canada
| | - Lisheng Wang
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Simon Sauve
- Centre for Biologics Evaluation, Biologic and Radiopharmaceutical Drugs Directorate, HPFB, Health Canada and WHO Collaborating Center for Standardization and Evaluation of Biologicals, Ottawa, ON, Canada
| | - Michael Rosu-Myles
- Centre for Biologics Evaluation, Biologic and Radiopharmaceutical Drugs Directorate, HPFB, Health Canada and WHO Collaborating Center for Standardization and Evaluation of Biologicals, Ottawa, ON, Canada.,Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Gary Van Domselaar
- National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB, Canada
| | - Xuguang Li
- Centre for Biologics Evaluation, Biologic and Radiopharmaceutical Drugs Directorate, HPFB, Health Canada and WHO Collaborating Center for Standardization and Evaluation of Biologicals, Ottawa, ON, Canada.,Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| |
Collapse
|
3
|
Horthongkham N, Athipanyasilp N, Pattama A, Kaewnapan B, Sornprasert S, Srisurapanont S, Kantakamalakul W, Amaranond P, Sutthent R. Epidemiological, Clinical and Virological Characteristics of Influenza B Virus from Patients at the Hospital Tertiary Care Units in Bangkok during 2011-2014. PLoS One 2016; 11:e0158244. [PMID: 27387488 PMCID: PMC4936745 DOI: 10.1371/journal.pone.0158244] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 06/12/2016] [Indexed: 11/19/2022] Open
Abstract
Influenza B virus, which causes acute respiratory infections, has increased in prevalence in recent years. Based on the nucleotide sequence of the hemagglutinin (HA) gene, influenza B virus can be divided into two lineages, Victoria and Yamagata, that co-circulate during the influenza season. However, analysis of the potential association between the clinical and virological characteristic and the lineage of influenza B viruses isolated in Thailand was lacking. To investigate influenza B virus genetically and determine its neuraminidase (NA) inhibitor susceptibility phenotype, a total of 6920 nasopharyngeal-wash samples were collected from patients with influenza-like illness between the years 2011 and 2014 and were screened for influenza B virus by real-time PCR. Of these samples, 3.1% (216/6920) were confirmed to contain influenza B viruses, and 110 of these influenza viruses were randomly selected for nucleotide sequence analysis of the HA and NA genes. Phylogenetic analysis of the HA sequences showed clustering into various clades: Yamagata clade 3 (11/110, 10%), Yamagata clade 2 (71/110, 64.5%), and Victoria clade 1 (28/110, 25.5%). The analysis of clinical characteristic demonstrated that the Victoria lineage was significantly associated with the duration of hospitalization, number of deceased cases, pneumonia, secondary bacterial infection and underlying disease. When combined with phylogenetic analysis of the NA sequences, four samples showed viruses with reassortant sequences between the Victoria and Yamagata lineages. Statistical analysis of the clinical outcomes and demographic data for the reassortant strains did not differ from those of the other strains in circulation. Oseltamivir-resistant influenza B viruses were not detected. Our findings indicated the co-circulation of the Victoria and Yamagata lineages over the past four cold seasons in Bangkok. We also demonstrated differences in the clinical symptoms between these lineages.
Collapse
Affiliation(s)
- Navin Horthongkham
- Department of Microbiology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Niracha Athipanyasilp
- Department of Microbiology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Archiraya Pattama
- Department of Microbiology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Bualan Kaewnapan
- Department of Microbiology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Suthatta Sornprasert
- Department of Microbiology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Surangrat Srisurapanont
- Department of Pathology, Faculty of Medicine, Srinakharinwirot University, Bangkok, Thailand
| | - Wannee Kantakamalakul
- Department of Microbiology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Palanee Amaranond
- Department of Blood transfusion, Faculty of Allied Health Science, Chulalongkorn University, Bangkok, Thailand
| | - Ruengpung Sutthent
- Department of Microbiology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
- * E-mail:
| |
Collapse
|
4
|
Ni F, Kondrashkina E, Wang Q. Structural basis for the divergent evolution of influenza B virus hemagglutinin. Virology 2013; 446:112-22. [PMID: 24074573 DOI: 10.1016/j.virol.2013.07.035] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 07/23/2013] [Accepted: 07/26/2013] [Indexed: 10/26/2022]
Abstract
Influenza A and B viruses are responsible for the severe morbidity and mortality worldwide in annual influenza epidemics. Currently circulating influenza B virus belongs to the B/Victoria or B/Yamagata lineage that was diverged from each other about 30-40 years ago. However, a mechanistic understanding of their divergent evolution is still lacking. Here we report the crystal structures of influenza B/Yamanashi/166/1998 hemagglutinin (HA) belonging to B/Yamagata lineage and its complex with the avian-like receptor analogue. Comparison of these structures with those of undiverged and diverged influenza B virus HAs, in conjunction with sequence analysis, reveals the molecular basis for the divergent evolution of influenza B virus HAs. Furthermore, HAs of diverged influenza B virus strains display much stronger molecular interactions with terminal sialic acid of bound receptors, which may allow for a different tissue tropism for current influenza B viruses, for which further investigation is required.
Collapse
Affiliation(s)
- Fengyun Ni
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA; Department of Bioengineering, Rice University, Houston, TX 77005, USA
| | | | | |
Collapse
|
5
|
Abstract
Here we report the crystal structure of hemagglutinin (HA) from influenza B/Hong Kong/8/73 (B/HK) virus determined to 2.8 A. At a sequence identity of approximately 25% to influenza A virus HAs, B/HK HA shares a similar overall structure and domain organization. More than two dozen amino acid substitutions on influenza B virus HAs have been identified to cause antigenicity alteration in site-specific mutants, monoclonal antibody escape mutants, or field isolates. Mapping these substitutions on the structure of B/HK HA reveals four major epitopes, the 120 loop, the 150 loop, the 160 loop, and the 190 helix, that are located close in space to form a large, continuous antigenic site. Moreover, a systematic comparison of known HA structures across the entire influenza virus family reveals evolutionarily conserved ionizable residues at all regions along the chain and subunit interfaces. These ionizable residues are likely the structural basis for the pH dependence and sensitivity to ionic strength of influenza HA and hemagglutinin-esterase fusion proteins.
Collapse
|
6
|
Tung CS, Goodman JL, Lu H, Macken CA. Homology model of the structure of influenza B virus HA1. J Gen Virol 2004; 85:3249-3259. [PMID: 15483238 DOI: 10.1099/vir.0.80021-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Influenza B virus is one of two types of influenza virus that cause substantial morbidity and mortality in humans, the other being influenza A virus. The inability to provide lasting protection to humans against influenza B virus infection is due, in part, to antigenic drift of the viral surface glycoprotein, haemagglutinin (HA). Studies of the antigenicity of the HA of influenza B virus have been hampered by lack of knowledge of its structure. To address this gap, two possible models have been inferred for this structure, based on two known structures of the homologous HA of the influenza A virus (subtypes H3 and H9). Statistical, structural and functional analyses of these models suggested that they matched important details of experimental observations and did not differ from each other in any substantive way. These models were used to investigate two HA sites at which viral variants appeared to carry a selective advantage. It was found that each of these sites coevolved with nearby sites to compensate for either size or charge changes.
Collapse
Affiliation(s)
- Chang-Shung Tung
- Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Joshua L Goodman
- Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Henry Lu
- Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Catherine A Macken
- Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| |
Collapse
|
7
|
Abed Y, Coulthart MB, Li Y, Boivin G. Evolution of surface and nonstructural-1 genes of influenza B viruses isolated in the Province of Québec, Canada, during the 1998-2001 period. Virus Genes 2003; 27:125-35. [PMID: 14501190 DOI: 10.1023/a:1025768308631] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
After 2 minor winter seasons, influenza B viruses were predominantly isolated in the Province of Quebec, Canada, during the 2000-2001 season representing 74% of laboratory-confirmed influenza viruses. We performed an antigenic study of the hemagglutinin (HA) protein and a molecular characterization of the HA1 region, nonstructural-1 (NS1) and neuraminidase (NA)/NB genes of 20 influenza B strains isolated in the Province of Quebec during the 1998-2001 period. Our isolates were compared to recent vaccine strains (B/Harbin/7/94 in 1998-1999, B/Yamanashi/166/98 in 1999-2000 and 2000-2001, and B/Sichuan/379/99 in 2001-2002). The hemagglutination inhibition (HI) test revealed that all isolates were different from B/Harbin/7/94 and were more related to the 2 other vaccine strains although precise identification was often impossible. Molecular analysis of the HA1 gene revealed that both B/Yamanashi/166/98-like and B/Sichuan/379/99-like isolates co-circulated during the 1998-1999 season whereas isolates from the 2 subsequent years were more related to B/Sichuan/379/99. Most isolates (8/9) of the 2000-2001 season contained a N126D substitution recently associated with altered antigenicity in recent influenza B/Yamagata/16/88-related viruses. Although the HA1 and NS1 protein sequences of viruses isolated during the 1998-1999 season were clearly different from those of the respective vaccine strain (B/Harbin/7/94), the NA protein sequence of those isolates was slightly more related to B/Harbin/7/94 than B/Yamanashi/166/98 suggesting distinct patterns of evolution for these genes. This study confirms the importance of a detailed molecular analysis for understanding the evolution of influenza B viruses.
Collapse
Affiliation(s)
- Yacine Abed
- Infectious Disease Research Center, Centre Hospitalier Universitaire de Québec, Québec City, Canada
| | | | | | | |
Collapse
|
8
|
|
9
|
Chan CH, Wu MC, Huang CT, Wu KG, Liu WT. Genetic characterization of the hemagglutinin of two strains of influenza B virus co-circulated in Taiwan. J Med Virol 1999; 59:208-14. [PMID: 10459158 DOI: 10.1002/(sici)1096-9071(199910)59:2<208::aid-jmv14>3.0.co;2-m] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Two isolates of influenza B virus were obtained in the spring of 1997. One strain, B/Taiwan/21706/97, was isolated from a patient who had acute tonsillitis. The other, B/Taiwan/3143/97, was isolated from a patient who was diagnosed with meningoencephalitis. This implies that the influenza B viruses not only cause respiratory symptoms but may also cause inflammation of the nervous system. Sequence analysis of the hemagglutinin (HA) gene, HA1 domain, indicated that there were remarkable amino acid changes in the strain B/Taiwan/3143/97 compared to B/Victoria/2/87, B/Yamagata/16/88, and B/Taiwan/7/88. The changes in the positions 116, 200, 238, 242, and 271 were correlated with receptor binding. Furthermore, a potential glycosylation site at position 233 was lost. In total, 30 amino acid changes were noted at positions ranging from 116 to 295. These changes may affect the antigenicity of the virus. Phylogenetic analyses also showed that the B/Taiwan/3143/97 was located in an independent lineage, when compared to the reference strains belonging to B/Victoria/2/87 and B/Yamagata/16/88 lineages. This supports the hypothesis that influenza B viruses with distinct genetic characteristic were co-circulated in Taiwan.
Collapse
Affiliation(s)
- C H Chan
- Institute of Microbiology and Immunology, School of Life Science, National Yang-Ming University (NYMU), Taipei, Taiwan, Republic of China
| | | | | | | | | |
Collapse
|
10
|
Yang P, Bansal A, Liu C, Air GM. Hemagglutinin specificity and neuraminidase coding capacity of neuraminidase-deficient influenza viruses. Virology 1997; 229:155-65. [PMID: 9123857 DOI: 10.1006/viro.1996.8421] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Neuraminidase (NA)-deficient mutant virus stocks have been obtained by passaging A/NWS/33HA-tern/Australia/G70c/75NA (H1N9) influenza virus in medium containing neuraminidase from Micromonospora viridifaciens and antiserum against the influenza NA. Growth of the resulting mutants is dependent on addition of bacterial neuraminidase to the medium. Nucleotide sequence analysis showed large single deletions in the NA genes, with both ends of the NA gene segments conserved. These RNA fragments all have the capacity to code for a peptide that contains the N-terminal "tail" and membrane-anchoring region of the NA, but the presence of this peptide has not been demonstrated in virions or infected cells. In contrast to the ease of selection of NA-deficient mutants from the H1N9 virus, no mutants were selected from three other viruses. The HA-coding segments of parental H1N9 and mutant NWSc-Mvi predict a change of Pro to His at residue 227 (H3 numbering), close to the receptor-binding site of H3 HA, compared to the HA of an H1N2 reassortant that contains the NWS/33 HA gene. This change may contribute to an altered HA specificity that allows selection of mutants that can infect cells in the presence of high levels of NA activity. It appears that the role of NA in influenza infection is to remove sialic acid from the HA rather than to destroy receptors on cells.
Collapse
Affiliation(s)
- P Yang
- Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City 73190, USA
| | | | | | | |
Collapse
|
11
|
Bourbeau J, Brisson C, Allaire S. Prevalence of the sick building syndrome symptoms in office workers before and after being exposed to a building with an improved ventilation system. Occup Environ Med 1996; 53:204-10. [PMID: 8704863 PMCID: PMC1128445 DOI: 10.1136/oem.53.3.204] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
OBJECTIVE To find if the prevalence of symptoms associated with sick building syndrome decreased among office workers after moving to a building with improved ventilation (after controlling for potential confounders). METHODS Workers in five buildings in 1991 all moved in 1992 into a single building with improved design, operation, and maintenance of the ventilation system. All buildings had sealed windows with mechanical ventilation, air conditioning, and humidification. Workers completed a self administered questionnaire during normal working hours in February 1991 and February 1992. The questionnaire encompassed symptoms of the eyes, nose and throat, respiratory system, skin, fatigue, headache, and difficulty concentrating, personal, psychosocial, and work related factors. During normal office hours of the same week environmental variables were measured. RESULTS The study population comprised 1390 workers in 1991 and 1371 workers in 1992 who represented more than 80% of the eligible population. The prevalence of most symptoms decreased when workers moved to the new building: skin (54%), respiratory system (53%), nose and throat (46%), fatigue (44%), headache (37%), eyes (23%). These findings were all significant and remained generally similar after controlling for personal, psychosocial, and work related factors. Furthermore, more than 60% of workers symptomatic in 1991 were asymptomatic in 1992 for all types of symptoms. In contrast, less than 15% of workers were asymptomatic in 1991 but symptomatic in 1992 for all types of symptoms. CONCLUSION In this study, the prevalence of most symptoms usually associated with the sick building syndrome decreased by 40% to 50% after workers were transferred to a building with an improved ventilation system. The results show that it is possible to diminish the prevalence of symptoms associated with the sick building syndrome among office workers occupying a building with mechanical ventilation, air conditioning, and sealed windows.
Collapse
Affiliation(s)
- J Bourbeau
- Public Health Department, Hôpital du St-Sacrement, Laval University
| | | | | |
Collapse
|