evidence: By contrast, we found that maternal COVID-19 vaccination during pregnancy was associated with a slightly increased risk of neonatal readmission in unadjusted analyses. We hypothesize the observed increase was due to depletion of susceptibles39; this is supported by the finding that a small proportion of infants in the unexposed group were more likely to be excluded from analyses of readmission either because they died during the birth admission or because their birth admission was longer than 28 days. In the weighted primary analysis and most subgroup/sensitivity analyses, the association between maternal vaccination and neonatal readmission was no longer significant and there was no increase in hospital readmission up to age 6 months.