Seroimmunity to diphtheria and tetanus among mother-infant pairs; the role of maternal immunity on infant immune response to diphtheria-tetanus vaccination.
BACKGROUND
This study was designed to determine the levels of immunity against diphtheria and tetanus in 110 mothers with/without diphtheria-tetanus toxoid (dT) vaccination during pregnancy and their two-month-old infants before diphtheria-tetanus-pertussis (DTP) immunisation, and also to assess the influence of pre-vaccination passive immunity on the infants' immune response to three doses of DTP vaccination.


METHODS
Sera from 110 mother-infant pairs before DTP vaccination and from 69 infants after receipt of three doses of DTP vaccine were tested to measure antidiphtheria-antitetanus toxin IgG levels, using a commercial enzyme immunoassay. History of dT toxoid vaccination of mothers at pregnancy was recorded.


RESULTS
20% of mothers did not receive dT vaccine. Among these 22 unvaccinated mothers, one (5%) and six (27%) were serologically susceptible to tetanus and diphtheria respectively. The mean concentrations of antibody titers were lower in unvaccinated than in vaccinated mothers: diphtheria 0.78 (0.30) IU/mL vs 0.31 (0.20), and tetanus 1.95 (1.20) IU/mL vs 0.51 (0.45), vaccinated mother vs unvaccinated. All infants (100%) acquired immunity against both infections after receipt of three doses of DTP vaccine. Pre-vaccination passive immunity did not influence the infants' immune response to vaccination: diphtheria 0.95 (0.40) vs 0.89 (0.25), and tetanus 2.30 (1.0) vs 2.30 (0.70), from passive immune infants before vaccination vs those without, respectively.


CONCLUSIONS
This study showed that diphtheria-tetanus toxoid components of DTP vaccine were highly immunogenic and maternal passive immunity did not affect the infants' immune response to DTP vaccination. Since there is a 23% missed opportunity for dT immunisation, efforts must be made to increase the coverage rate of this highly immunogenic vaccine in order to sustain protection against diphtheria and tetanus in mothers and their infants..
Saffar
Mohammed-Jafar
MJ
Pediatric Infectious Diseases Ward, Boali Cina Hospital, Mazandaran University of Medical Sciences, Sari, Iran. saffar@softhome.net
Khalilian
Ali-Rezas
AR
Ajami
Abolghasem
A
Saffar
Hiva
H
Qaheri
Abbas
A
D000907:Antibodies, Bacterial / Q000097:blood*; D004165:Diphtheria / Q000276:immunology*; D015721:Diphtheria-Tetanus-Pertussis Vaccine / Q000008:administration & dosage / Q000276:immunology*; D005260:Female; D006801:Humans; D007110:Immunity, Active / Q000276:immunology; D007112:Immunity, Maternally-Acquired / Q000276:immunology*; D007115:Immunization Schedule; D007223:Infant; D007492:Iran; D008297:Male; D011247:Pregnancy; D013742:Tetanus / Q000276:immunology*
D000907:Antibodies, Bacterial; D015721:Diphtheria-Tetanus-Pertussis Vaccine