When public health officials make policies about when and how vaccination programs are implemented, they must weigh the benefits and risks of how infectious diseases spread throughout the country. However, these analyses are often based on national-level data and, in some countries, may overlook nuances at the local level.
Vaccination, on the other hand, reduces the amount of circulating virus, meaning individuals who were not vaccinated as children are less likely to be infected with rubella by adolescence or adulthood, Ferrari explained. As a result, even as the total number of rubella cases goes down with vaccination, the number of rubella infections in people of reproductive age -- who were neither infected nor vaccinated as children -- increases, putting those pregnancies at risk of CRS.
"We grounded the current infection risk and potential pregnancies at risk in strong empirical data and real-world phenomena," Ferrari said."Parts of the country can already vaccinate more than 80% of kids, based on their current rate of measles vaccination, but low vaccination coverage in the north is a barrier to introduction across the whole country under the current recommendation.