Sero-epidemiology of measles immunoglobulin G antibodies among newborns from South-East Asia and sub-Saharan Africa: an observational, multicenter study

Objectives

To investigate the transplacental acquisition of measles immunoglobulin (Ig)G in newborns at delivery in Bangladesh, Bhutan, India, Ethiopia, Mozambique, Kenya, Nigeria, Mali, and South Africa.

Methods

Archived cord serum, from a multicenter study on Group B Streptococcus, were tested for measles IgG using a commercial enzyme link immunosorbent assay (ELISA). We tested 323 randomly selected samples from each of the sites. Models using various measles antibody decay rates in infancy were explored.

Results

Overall, 2,907 cord serum samples were analyzed. At birth, 49.9% of newborns were measles IgG seronegative. Measles seronegativity ranged from 21.7% in Nigeria to 73.4% in Bhutan. The adjusted odds of seronegativity in infants of mothers born after measles vaccination implementation was 1.78 times that for infants born to unvaccinated mothers (adjusted odds ratio 1.78; 95% confidence interval 1.43-2.21; P <0.001). Modeling measles-IgG kinetics predicted that 70.8%, 88.3%, and 100% of infants would be seronegative by 2, 4, and 6 months, respectively, without further exposure.

Conclusions

Our findings suggest low transplacental acquisition of measles IgG in newborns, which is likely to yield susceptibility to measles infection at a very young age. The currently recommended measles vaccine schedules in low- and middle-income countries (LMICs), with the first dose recommended from 9 months of age and onward, warrant reconsideration, including the need for earlier dosing schedules.