Post-authorization safety surveillance of a liquid pentavalent vaccine in Guatemalan children.
OBJECTIVE
Combination vaccines have improved the efficiency of delivery of new vaccines in low and middle-income countries. Post-authorization monitoring of adverse events (AEs) after vaccination with a liquid pentavalent DTwP-HepB-Hib combination vaccine was conducted in Guatemalan infants.


METHODS
A prospective observational safety study of the incidence of medical attended events (MAEs) and serious adverse events (SAEs) in children who received pentavalent and oral polio vaccines at 2, 4 and 6 months of age was conducted in two clinics at the Institute of Guatemala. Parents were contacted by telephone after each dose. All outpatient, emergency department visits, and hospitalizations were monitored. A self-controlled analysis was conducted to determine if there was evidence of increased risk of MAEs or SAEs following vaccines as compared to control time windows.


RESULTS
Of 3000 recruited infants, 2812 (93.7%) completed the third dose and 2805 (93.5%) completed follow-up. Ten AEs in eight infants, of which four SAEs in four infants, were classified as related to the vaccine. Thirteen deaths were reported due to common illnesses of infancy, and none were judged to be related to the vaccine. The mortality rate (4.4 per 1000) was lower than expected for the population. The incidence-rate-ratio for healthcare visits was lower in post-vaccination time windows than for control windows; after the first vaccine dose, the rate ratios for the risk periods of 0-1, 2-6, and 7-30 days post-vaccination were 0.3, 0.5, and 0.7, respectively (all statistically significantly different from the reference value of 1.0 for the 31-60 day control period).


CONCLUSIONS
The liquid pentavalent vaccine was associated with lower rates of health care visits and not associated with increases in SAEs or hospitalizations. Systems can be set up in low to middle income countries to capture all health care visits to monitor the safety of new vaccines.
Department of Pediatrics, School of Medicine, University of Colorado, Aurora, CO, USA; Department of Epidemiology, Colorado School of Public Health, University of Colorado, Aurora, CO, USA; Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA. Electronic address: edwin.asturias@ucdenver.edu.
Edwin J
EJ
Asturias
Ingrid L
IL
Contreras-Roldan
Malathi
M
Ram
Ana J
AJ
Garcia-Melgar
Vilma
V
Morales-Oquendo
Katharina
K
Hartman
Martina
M
Rauscher
Lawrence H
LH
Moulton
Neal A
NA
Halsey
D016907:Adverse Drug Reaction Reporting Systems / Q000706:statistics & numerical data*; D015721:Diphtheria-Tetanus-Pertussis Vaccine / Q000009:adverse effects*; D064420:Drug-Related Side Effects and Adverse Reactions / Q000453:epidemiology; D005260:Female; D006166:Guatemala; D018073:Haemophilus Vaccines / Q000009:adverse effects*; D017325:Hepatitis B Vaccines / Q000009:adverse effects*; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D007114:Immunization / Q000009:adverse effects / Q000706:statistics & numerical data; D017589:Immunization Programs; D007223:Infant; D008297:Male; D011358:Product Surveillance, Postmarketing; D011446:Prospective Studies; D017778:Vaccines, Combined / Q000009:adverse effects
D015721:Diphtheria-Tetanus-Pertussis Vaccine; C524361:DtwP-HepB-Hib vaccine; D018073:Haemophilus Vaccines; D017325:Hepatitis B Vaccines; D017778:Vaccines, Combined
DTP; Hib; Liquid pentavalent; Post licensure surveillance; Safety