title: Effect of month of vaccine administration on antibody responses in The Gambia and Pakistan.
abstract: OBJECTIVE
  To explore the relationship between calendar month of administration and antibody (Ab) response to vaccination in subjects from The Gambia and Pakistan, two countries with distinct patterns of seasonality.
  
  
  METHODS
  Three cohorts were investigated: Responses to rabies and pneumococcal vaccine were assessed in 472 children (mean age 8 years, males 53%) from rural Gambia. Responses to tetanus, diphtheria and hepatitis B (HBsAg) were investigated in 138 infants also from The Gambia (birth to 52 weeks of age, males 54%). Responses to rabies and Vi typhoid vaccines were assessed in 257 adults from Lahore, Pakistan (mean age 29.4 years, males 57%).
  
  
  RESULTS
  In Gambian children, significant associations were observed between month of vaccination and Ab response for the pneumococcal and rabies vaccines. As no consistent pattern by month was observed between the responses, it is assumed that different immunomodulatory stimuli or mechanisms were involved. In Pakistani adults, a significant pattern by month of vaccination was observed with both rabies and typhoid vaccine. No monthly influences were observed in the infant study to the tetanus, diphtheria or the HbsAg vaccines.
  
  
  CONCLUSIONS
  Antibody responses to certain specific vaccines are influenced by month of administration. Further research is required to elucidate the precise mechanisms explaining these observations, but a co-stimulatory effect of seasonally variable environmental antigens is a likely cause. Future studies of Ab response to vaccination in countries with a seasonally dependent environment should consider month of vaccination when interpreting study findings.
authors.affiliation: MRC International Nutrition Group, Nutrition and Public Health Intervention Research Unit, London School of Hygiene and Tropical Medicine, London, UK. sophie.moore@lshtm.ac.uk
authors.forename: Sophie E
authors.initials: SE
authors.lastname: Moore
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Collinson
authors.forename: Anthony J C
authors.initials: AJ
authors.lastname: Fulford
authors.forename: Fehmida
authors.initials: F
authors.lastname: Jalil
authors.forename: Claire-Anne
authors.initials: CA
authors.lastname: Siegrist
authors.forename: David
authors.initials: D
authors.lastname: Goldblatt
authors.forename: Lars A
authors.initials: LA
authors.lastname: Hanson
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Prentice
mesh_terms: D000328:Adult; D000907:Antibodies, Bacterial / Q000276:immunology*; D000914:Antibodies, Viral / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D004168:Diphtheria Toxoid / Q000008:administration & dosage / Q000276:immunology; D005260:Female; D005714:Gambia; D017325:Hepatitis B Vaccines / Q000008:administration & dosage / Q000276:immunology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D010154:Pakistan; D022242:Pneumococcal Vaccines / Q000008:administration & dosage / Q000276:immunology; D011819:Rabies Vaccines / Q000008:administration & dosage / Q000276:immunology; D012423:Rural Health; D012621:Seasons; D013744:Tetanus Toxin / Q000008:administration & dosage / Q000276:immunology; D014436:Typhoid-Paratyphoid Vaccines / Q000008:administration & dosage / Q000276:immunology; D014612:Vaccines / Q000008:administration & dosage* / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D000914:Antibodies, Viral; D004168:Diphtheria Toxoid; D017325:Hepatitis B Vaccines; D022242:Pneumococcal Vaccines; D011819:Rabies Vaccines; D013744:Tetanus Toxin; D014436:Typhoid-Paratyphoid Vaccines; D014612:Vaccines