Premature infants and maternal pertussis immunization
Wat erin zit
Re-emergence of pertussis despite high vaccination coverage in western countries, results in increased risk for severe and even fatal pertussis among newborns. For this reason, late 2015 the Dutch Health Council (HC) advised to offer 3rd trimester pertussis vaccination to pregnant women. At the start of the maternal pertussis programme late 2019, the maternal Tdap was advised from 22w of gestation onwards.
Preterms, accounting for 8% of newborns in the Netherlands, are at highest risk for severe pertussis leading to prolonged hospital and intensive care admissions and sometimes death. Recently, it has become evident that despite 3rd trimester vaccination, preterms remain at high risk because the vaccination is likely given too late for sufficient antibody transfer. For this vulnerable group 2nd trimester vaccination may offer better protection because of extended time for antibody transfer.
To date, most countries recommend 3rd trimester vaccination to protect young, not yet (fully) vaccinated infants. Data from England show 91% effectiveness against infant pertussis after maternal Tetanus- diphtheria -acellular Pertussis (Tdap) vaccination in the 3rd trimester.
Studies focussing on preterms and protection after maternal vaccination are scarce. Two observational studies reported on effectiveness and antibody levels in cord blood of 2nd trimester vaccination in term infants. While one study showed significantly higher antibody levels after 2nd trimester vaccination (13-25 gestational weeks; GW), another study showed decreased effectiveness of 2nd trimester (<27 GW) vaccination. Only one study concerned antibody transfer in preterms and reported higher antibody levels after 2nd (n=37) than after 3rd (n=48) trimester vaccination.
Aiming to contribute to setting optimal vaccine strategy of maternal pertussis vaccination in the Netherlands and elsewhere and particular for the most vulnerable group of preterms, we propose a study that compares pertussis antibody levels in preterms and terms after 2nd trimester maternal vaccination. We can compare these to data we have on 3rd trimester Tdap in terms. In addition to adequate antibody levels, success of 2nd trimester vaccination depends on acceptance of this strategy by pregnant women and professionals.
Our primary endpoint is IgG anti-pertussis toxin (Pt) antibody concentration in preterms and terms at 2m of age,
Pt is considered the most relevant antibody for protection against clinical pertussis. Secondary endpoints are e.g. pertussis specific antibody concentrations in preterms and terms in cord blood and in women at delivery. Determinants of acceptance of 2nd trimester maternal vaccination are also a secondary endpoint.
Antibody concentrations will be assessed in serum, using a fluorescent bead-based multiplex immunoassay, with required blood volume of minimal 100µl.
Bestanden en diensten
- landingpageHTML · rivm.nlRIVM webpaginaOpenen