Seroprevalence of Pertussis in School-entry Age Children in Libya, A Cross-sectional Study
Objective: In Libya, no pertussis booster doses are administered to children
after 18 months of age. In light of evidence of waning of vaccine-induced
immunity to pertussis, this study aimed to evaluate the waning
of immunity in vaccinated school-entry age children, as measured by
susceptibility to infection at population level. For this purpose, IgG and
IgA levels were measured as markers of recent (infection in the last 6
months) and non-recent infections (infection in the last 12 months).
Material and Methods: This was a cross sectional study undertaken in
Tripoli, in February 2015. Children of school-entry age (> 5 to ≤ 7 years)
were recruited on convenience basis at vaccination centers. Sera were
tested for antibodies to pertussis.
Results: Samples from791 children (421 males and 370 females, mean
age 6.50 were tested). All of the participants had received 4 doses of
Whole cell pertussis containing vaccine in the first 2 years of life. The
prevalence of recent and non-recent pertussis infection were 4.8% and
2.5%, respectively. The proportion of children with undetectable level of
IgG was 76.1%.
Conclusion: The findings of this study showed significant circulation of
Bordetella pertussis among vaccinated children by school-entry age. The
circulation of B. pertussis in this population may be an indirect sign of
waned immunity, which is simply corroborated by the absence of detectable
antibodies in 76.1% of the children. arabic 14 English 76
Suleiman Abusrewil, Abdulla Bashein(1-2019)
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