title: Factors determining anti-poliovirus type 3 antibodies among orally immunised Indian infants.
abstract: Among the three poliovirus serotypes, the lowest responses after vaccination with trivalent oral polio vaccine (tOPV) are to serotype 3. Although improvements in routine immunisation and supplementary immunisation activities have greatly increased vaccine coverage, there are limited data on antibody prevalence in Indian infants.
  
  
  
  Children aged 5-11months with a history of not having received inactivated polio vaccine were screened for serum antibodies to poliovirus serotype 3 (PV3) by a micro-neutralisation assay according to a modified World Health Organization (WHO) protocol. Limited demographic information was collected to assess risk-factors for a lack of protective antibodies. Student's t-test, logistic regression and multilevel logistic regression (MLR) model were used to estimate model parameters.
  
  
  
  Of 8454 children screened at a mean age of 8.3 (standard deviation [SD]-1.8) months, 88.1% (95% confidence interval (CI): 87.4-88.8) had protective antibodies to PV3. The number of tOPV doses received was the main determinant of seroprevalence; the maximum likelihood estimate yields a 37.7% (95% CI: 36.2-38.3) increase in seroprevalence per dose of tOPV. In multivariable logistic regression analysis increasing age, male sex, and urban residence were also independently associated with seropositivity (Odds Ratios (OR): 1.17 (95% CI: 1.12-1.23) per month of age, 1.27 (1.11-1.46) and 1.24 (1.05-1.45) respectively).
  
  
  
  Seroprevalence of antibodies to PV3 is associated with age, gender and place of residence, in addition to the number of tOPV doses received. Ensuring high coverage and monitoring of response are essential as long as oral vaccines are used in polio eradication.
authors: Division of Gastrointestinal Sciences, Christian Medical College, Vellore, India. Electronic address: saravanakumar@cmcvellore.ac.in.
authors: Saravanakumar Puthupalayam
authors: SP
authors: Kaliappan
authors: Division of Gastrointestinal Sciences, Christian Medical College, Vellore, India. Electronic address: srinistat09@gmail.com.
authors: Srinivasan
authors: S
authors: Venugopal
authors: Division of Gastrointestinal Sciences, Christian Medical College, Vellore, India. Electronic address: sidharthgiri@cmcvellore.ac.in.
authors: Sidhartha
authors: S
authors: Giri
authors: Division of Gastrointestinal Sciences, Christian Medical College, Vellore, India. Electronic address: irapraharaj@cmcvellore.ac.in.
authors: Ira
authors: I
authors: Praharaj
authors: Division of Gastrointestinal Sciences, Christian Medical College, Vellore, India. Electronic address: arun.karthikeyan@cmcvellore.ac.in.
authors: Arun S
authors: AS
authors: Karthikeyan
authors: Division of Gastrointestinal Sciences, Christian Medical College, Vellore, India. Electronic address: sudhirbabji@cmcvellore.ac.in.
authors: Sudhir
authors: S
authors: Babji
authors: Department of Community Health, Christian Medical College, Vellore, India. Electronic address: jacob@cmcsph.org.
authors: Jacob
authors: J
authors: John
authors: Division of Gastrointestinal Sciences, Christian Medical College, Vellore, India. Electronic address: jpmuliyil@gmail.com.
authors: Jayaprakash
authors: J
authors: Muliyil
authors: Department of Infectious Disease Epidemiology, Imperial College London, United Kingdom. Electronic address: n.grassly@imperial.ac.uk.
authors: Nicholas
authors: N
authors: Grassly
authors: Division of Gastrointestinal Sciences, Christian Medical College, Vellore, India. Electronic address: gkang@cmcvellore.ac.in.
authors: Gagandeep
authors: G
authors: Kang
mesh_terms: D057134:Antibodies, Neutralizing / Q000097:blood; D000914:Antibodies, Viral / Q000097:blood*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007194:India; D007223:Infant; D016013:Likelihood Functions; D008297:Male; D009500:Neutralization Tests; D011051:Poliomyelitis / Q000517:prevention & control; D017955:Poliovirus / Q000145:classification; D011054:Poliovirus Vaccine, Inactivated / Q000008:administration & dosage / Q000627:therapeutic use*; D011055:Poliovirus Vaccine, Oral / Q000008:administration & dosage / Q000627:therapeutic use*; D012307:Risk Factors; D016036:Seroepidemiologic Studies; D065288:Serogroup
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D011054:Poliovirus Vaccine, Inactivated; D011055:Poliovirus Vaccine, Oral
keywords: Immunogenicity; India; Infants; OPV; Poliovirus; Seroprevalence