title: Seroprevalence of Bordetella pertussis antibodies in adults in Hungary: results of an epidemiological cross-sectional study.
abstract: Pertussis (whooping cough) is well known to be underreported, particularly among adults, who can act as an infectious reservoir, potentially putting susceptible newborns at risk of serious illness. The purpose of this study was to estimate the seroprevalence of pertussis in adults in Hungary.
  
  
  
  This epidemiological, cross-sectional study was conducted in adults in five general practitioners' practices in Hungary. Serum anti-pertussis toxin immunoglobulin G (anti-PT IgG) antibody levels were analyzed using enzyme-linked immunosorbent assay. Sera were classified following manufacturer's instructions as: strongly indicative of current/recent infection (≥1.5 optical density [OD] units); indicative of current/recent infection (≥1.0 OD units); seropositive (>0.3 OD units); or seronegative (≤0.3 OD units). Logistic regression was performed to describe the associations between seroprevalence and various characteristics.
  
  
  
  Between 24thApril 2014 and 24thApril 2015, 1999 adults (60.6% female; mean age 47.4 ± 17.7 years) were included in the analysis. A total of 14.8% were seropositive for anti-PT IgG, 1.1% had a level indicative of current/recent infection, and 0.1% had a level strongly indicative of current/recent infection. Logistic regression showed significant relationships between increased rates of seropositivity and: age ≥60 years (odds ratio [OR], 1.97; 95% confidence interval [CI], 1.39-2.80; p = .0002) or 18-29 years (OR, 1.67; 95% CI, 1.13-2.46; p = .0094) vs. 45-59 years; former smoker (OR, 1.46; 95% CI, 1.08-1.97; p = .014) or current smoker (OR, 1.38; 95% CI, 1.01-1.89; p = .045) vs. never smoker; and male (OR, 1.30; 95% CI, 1.01-1.68; p = .041) vs. female. Also, between increased rates of probable current/recent infection and current smoker (OR, 7.50; 95% CI, 2.32-24.31; p = .0008) or former smoker (OR, 4.07; 95% CI, 1.21-13.64; p = .023) vs. never smoker.
  
  
  
  Approximately 85% of the adults studied were seronegative and therefore susceptible to pertussis infection. Approximately 1% had anti-PT IgG levels indicative of current/recent pertussis infection, which could potentially be transmitted to susceptible young infants. Vaccination of adults is a key way to indirectly protect infants.
  
  
  
  Clinical Trials.gov NCT02014519 . Prospectively registered 12 December 2013.
authors.affiliation: Faculty of Medicine, Department of Family Medicine, Semmelweis University, Kútvölgyi út 4, Budapest, 1125, Hungary.
authors.forename: Péter
authors.initials: P
authors.lastname: Torzsa
authors.affiliation: GSK, CDOC-B, #5 Embassy Links, S.R.T. Road, Bangalore, 560052, India.
authors.forename: Raghavendra
authors.initials: R
authors.lastname: Devadiga
authors.affiliation: GSK, Avenue Fleming 20, Wavre, 1300, Belgium. monica.x.tafalla@gsk.com.
authors.forename: Monica
authors.identifier: 0000-0001-6843-3943
authors.initials: M
authors.lastname: Tafalla
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000907:Antibodies, Bacterial / Q000097:blood*; D001886:Bordetella pertussis / Q000276:immunology*; D003430:Cross-Sectional Studies; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D006814:Hungary / Q000453:epidemiology; D007074:Immunoglobulin G / Q000097:blood; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D037342:Pertussis Toxin / Q000276:immunology; D016036:Seroepidemiologic Studies; D014917:Whooping Cough / Q000453:epidemiology* / Q000276:immunology; D055815:Young Adult
chemical_list: D000907:Antibodies, Bacterial; D007074:Immunoglobulin G; D037342:Pertussis Toxin
keywords: Bordetella pertussis; Epidemiology; Hungary; Seroprevalence