We estimate that there are 350 to 500 million acute episodes of malaria each year.

我们估计每年发生3.5亿至5亿例急性疟疾。

youdao

Its estimated children under five suffer between six and 10 fever-related episodes of malaria each year.

据估计，五岁以下的儿童每年患伴有高烧症状的疟疾的次数介于6 - 10次之间。

youdao

"You see children getting many episodes of malaria and gradually building up their immune response.

VOA: standard.2010.01.20

One study reported that the vaccine candidate was 53% effective in preventing episodes of clinical malaria in children five to 17 months old.

WSJ: Defeat Malaria? Yes We Can.