（仮）パンデミックに関する英語表現集

基礎疾患、持病、既往症

underlying chronic conditions
underlying health conditions
underlying health issues
pre-existing medical conditions
名詞句
※ほか、表現はたくさんあるので、また遭遇したら書き加えていきたい。要は形容詞として「基礎」のところにunderlying, pre-existingといった語句を使うということ。（日本語から英語に翻訳する場合、「基礎」を直訳しないこと。）

But it appears people who are older, those with weakened immune systems and people who have underlying chronic conditions, including heart disease, diabetes, or asthma, are more at risk of severe effects if they do catch it.
https://www.bbc.com/news/health-51703892

People at higher risk include those who are over 70, regardless of whether they have a medical condition or not, and people under 70 with any of the following underlying health conditions: ...
https://www.bbc.com/news/health-51703892

Chloe Middleton, who died on Saturday, is believed to be the UK's youngest victim with no underlying health issues, according to Sky News.
https://www.insider.com/coronavirus-chloe-middleto...

In the event of a spike in cases, U.S. citizens with pre-existing medical conditions may not be able to receive the medical care ...
https://jp.usembassy.gov/health-alert-us-embassy-t...

どうでもいいことだけど、日本の地方自治体や官公庁のサイトで「多言語化」ボタンを使うことで利用することになる某K電社の機械翻訳――「新型コロナウイルス」の「新型」を "new-style" と、「（病気の）流行」を "fashion" と出力したことでおなじみ――では、「基礎疾患」と入れて "underlying health conditions" などと返ってくる確率はほぼないと思う。