Nine COVID-19 patients among Shanghai's surging number of infections are in serious condition, mostly seniors with underlying diseases and without coronavirus vaccination.Apart from a 33-year-old patient, all the other cases in severe condition are between 70 and 93 years old. They all have serious underlying diseases, such as severe immune disease, advanced tumor, severe cardiovascular and cerebrovascular diseases or organ failure, said Wu Qianyu, a senior Shanghai Health Commission official.None of them has taken the COVID-19 vaccine, she told the city's daily COVID-19 press briefing.