In an attempt to address the rise in pertussis cases in developed communities once thought immune to any resurgence of the deadly infant disease, the Rohani lab explores maternal immunization that has been proposed, this far, as an effective strategy for protecting neonates, who are at higher risk of severe pertussis disease and mortality. They theorize that if maternally derived antibodies adversely affect the immunogenicity of the routine schedule, through blunting effects, they may observe a gradual degradation of herd immunity. ‘Wasted’ vaccines would result in an accumulation of susceptible children in the population, specifically leading to an overall increase in incidence in older age groups. In their Perspective, The Rohani lab discusses potential long-term epidemiological effects of maternal immunization, as determined by possible immune interference outcomes.
They perspective concluded that though maternal pertussis immunization is safe for both mother and infant and is currently recommended in Australia, Belgium, Brazil, Portugal, the UK and the US, in response to the rise in incidence. Its principal aim is to reduce pertussis mortality and morbidity in neonates. There is good reason to stress the direct benefits of maternal immunization to both mother and infant. However, its potential adverse effects on routine vaccination efficacy and the subsequent long-term epidemiological legacy remain the subject of debate
Given these unknowns, the Rohani lab developed a modeling study in an effort to predict the magnitude and time scale of potential effects of maternal antibody interference at the population level. Their study identified a trade-off between the direct protection of infants via maternal immunization and the reduced indirect effects of herd immunity, leading to a gradual increase in incidence among older age cohorts.
However, the researchers concluded that further work must be conducted to shed light on the nature of any interference effect. Specifically, they stress the importance of establishing whether interference leads to an increase in vaccine failure, reduces the protective effects of the vaccine or affects the duration of protection. By integrating information gleaned from clinical and immunological studies within epidemiological transmission models, the effectiveness of alternative strategies can be evaluated.