Impact of the two-dose rubella vaccination regimen on incidence of rubella seronegativity in gravidae aged 25 years and younger

Abstract

ObjectiveThis study compared the incidence of rubella seronegativity among gravidae of 25 year-old and younger, between those born in Hong Kong after 1983 when the two-dose rubella vaccination was implemented, versus gravidae born before, to examine the impact of the two-dose regimen.MethodsIn this retrospective cohort study, the incidence of antenatal rubella seronegativity in our parturients managed in1997-2015 was analysed by their age from ≤16 to 25 years, and the effect of year of birth was determined adjusting for confounding factors including teenage status, obstetric history, anthropometric factors, and health parameters including anaemia, thalassaemia trait and hepatitis B carrier status.ResultsAmong the 12743 gravidae, the 6103 gravidae born after 1983 had overall higher rubella seronegativity (9.1% versus 4.4%, OR 2.061, 95% CI 1.797–2.364), with significant difference (p = 0.006) and inverse correlation (p<0.001) with age, in contrast to the 6640 gravidae born in/before 1983 whom there was significant difference (p = 0.027) but a positive correlation (p = 0.008) with age. For each year of age, the former had significantly higher incidence of rubella seronegativity except for those of ≤16 years. Regression analysis confirmed that birth after 1983 was independently associated with rubella seronegativity (aOR 2.207, 95% CI 1.902–2.562).ConclusionThere was a significant trend between rubella seronegativity with age in young gravidae, but the pattern was opposite between gravidae born after versus in/before 1983, with the former having a higher incidence of seronegativity at all ages. Young women covered by the two-dose rubella immunisation programme have a paradoxically higher incidence of rubella seronegativity.

Impact of Maternal BMI on Rubella Nonimmunity at Antenatal Screening

“…This led to the conclusion that the mumps‐measles‐rubella program is probably effective only at preventing childhood rubella (). When the impact of the two‐dose rubella vaccination regimen on the incidence of rubella seronegativity among young gravidas was examined, we found that high BMI was independently associated with rubella seronegativity (), which was confirmed in this study that included all pregnant women regardless of age.…”

Response to third rubella vaccine dose

“…This is mainly because reports of failure to sustain long-term high-level rubella antibody levels in a vaccinated population. 15,[20][21][22] Further similar results may be expected following known decreases in childhood vaccination coverage. 22 The correlates of protection in a vaccinated population may differ from those in an unvaccinated population, and a lower anti-rubella IgG concentration may be sufficient if the virus is no longer circulating.…”

“…A study from Hong Kong has shown that a higher proportion of women, who were covered by two-dose rubella vaccinations, were seronegative compared to those born before the vaccinations were implemented. 15 Similarly, a previous study conducted in Norway focusing on seroprevalence among pregnant women, found that women, born before the national childhood vaccination program included two doses of MMR vaccine, had higher antibody concentrations compared to those born after. 16 This is may be due to the effect afforded by exposure to the circulating virus, while the immune response to the vaccine may be less persistent.…”

Seroprevalence and durability of rubella virus antibodies in a highly immunized population

“…While existing data is limited and often conflicting, studies have suggested that obesity is a contributing factor to poor vaccine responses as well as declining antibody titers [25]. A report by Hui and colleagues found that higher BMI was associated with rubella seronegativity in a young cohort (< 25 years of age) from Hong Kong [56]; alternatively, Siberry et al found no association between obesity and rubella vaccine responses in a study of children in the U.S. with perinatal exposure to HIV [57]. Interestingly, a comparative study of H1N1 influenza vaccine responses in healthy, overweight, and obese individuals found that influenza-specific antibody titers declined in the year following vaccination, and this decline was associated with higher BMI [27].…”