Expressions of condolences have flooded social media for the parents of a three-year-old girl who has become Hong Kong’s youngest Covid-related fatality.

The girl had no underlying medical issues and was in critical condition after being admitted to Prince of Wales Hospital in Sha Tin on Saturday. She was transferred the next day to an intensive care unit at Hong Kong Children’s Hospital at Kai Tak, where she died at 8.37pm on Tuesday.

She was one of the two Covid-related fatalities announced on Tuesday night. The other was a 100-year-old chronically ill woman, the city’s oldest Covid-related death, who tested preliminary-positive for the virus on Monday.

Hong Kong’s official tally of confirmed cases stood at 26,670, with 227 related deaths.

“My deepest condolences to her family,” Lam Tai-hing, chair professor in community medicine at the University of Hong Kong, wrote on Twitter:

Another Twitter user wrote: “Rest in peace, little angel. I’m sending all my good wishes to your mom & dad. This #covid wave has been so hard to watch.”

Professor Lau Yu-lung, a paediatrician and member of the government’s Advisory Panel on Covid-19 Vaccines and Scientific Committee on Vaccine Preventable Diseases, earlier said the young children’s early stages of physical development made them more prone to serious complications after contracting respiratory viruses.

“Babies or those aged two to three have narrow nasal passages and air tubes, so if there is [secretion] there, serious problems are more likely to develop,” he said.

Last Friday, a four-year-old boy who was sent to Pok Oi Hospital after vomiting and collapsing at his home in Yuen Long was certified dead. He tested preliminary-positive for Covid-19.

Health officials on Sunday revealed that out of 8,900 confirmed cases admitted to hospital since January 31, 520, or 5.8 per cent, were younger than six. About 4 per cent of the city’s total number of Covid-19 patients were aged four or younger.

To cope with the exponential surge of infections, health authorities said the elderly, children and patients in serious condition would be given priority for isolation beds. They urged younger patients with mild or no symptoms to wait patiently at home.

Authorities also announced on Sunday that the inoculation age for the Chinese-made Sinovac jab would be lowered from five to three years on Tuesday, while children aged five to 11 will be able to receive the German-produced BioNTech vaccine starting on Wednesday.