To assess the relationship between the prevalence of vitamin a deficiency among pregnant women and the effect of neonatal vitamin a supplementation on infant mortality.
That could be because doctors are more nervous about the effects if flu on pregnant women and are more likely to admit them, but the death rate among pregnant women is high.
3
从既往的大流行事件和流感高发季节所观察到的患病率和死亡率来看,孕妇发生流感感染的危险特别高。
Pregnant women are considered at special risk for influenza infection based on morbidity and mortality from previous pandemic events and from intense influenza seasons.