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Amaral, Kyle

University of British Columbia

Pertussis disease is most severe in young infants. Tetanus-diphtheria-acellular pertussis (Tdap) vaccine given in pregnancy increases anti-pertussis antibodies transferred to the fetus, protecting young infants from severe pertussis disease. However, infants born to Tdap-vaccinated mothers may experience immunomodulation, leading to decreased antibody responses to their own pertussis vaccines. Many low-to-middle income countries have a high incidence of pertussis disease and deaths in young infants, but Tdap is not recommended due to the lack of data, including data on the use in pregnant women living with human immunodeficiency virus (HIV). I evaluated anti-pertussis immunogenicity and antibody avidity in pregnant people living with and without HIV in Uganda that received Tdap in pregnancy, and their newborns. I hypothesized that Tdap-vaccinated pregnant people would have higher anti-pertussis antibodies compared with those that received tetanus-diphtheria (Td) vaccine, and infants born to Tdap-vaccinated mothers would have a modulated antibody response to their pertussis vaccines. Additionally, the impact of different diphtheria-tetanus-acellular pertussis (DTaP) vaccine schedules and products on immunomodulation in infants have not been explored. I evaluated 2+1 and 3+1 dose schedules with different vaccine products as a booster in children from Quebec. I hypothesized that children that received a 3+1 dose schedule would have higher antibodies and lower immunomodulation compared with children that received 2+1 doses of DTaP vaccine. Anti-pertussis toxin (PT), -filamentous hemagglutinin (FHA), and -pertactin (PRN) immunoglobulin G (IgG) concentrations were quantified by an enzyme-linked immunosorbent assay (ELISA), and anti-PT IgG avidity was measured by a modified ELISA. I found that people that received Tdap in pregnancy had higher total anti-PT and anti-FHA IgG concentrations compared to Td-vaccinated pregnant people, regardless of HIV-status. Infants from Tdap-vaccinated mothers had lower anti-PT IgG concentration after their primary series compared with infants from Td-vaccinated mothers, regardless of HIV-exposure. The proportion of antibodies with different avidities was similar between those that received the same vaccine, regardless of HIV-status. Receiving 3+1 doses compared to 2+1 doses of DTaP led to significantly higher total anti-PT, FHA, and PRN IgG concentrations with similar avidity between all groups. Overall, pertussis vaccines increase anti-pertussis antibodies, regardless of HIV-status and age.

Text

2025-04-30

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/87886

Experimental Medicine

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/