Two primary school teachers are fighting for their lives in intensive care after being taken ill with coronavirus.
Parents were informed in a newsletter that the two staff members were being treated in intensive care.
Graeme Dow, who is in charge of Anchorsholme Academy, in Thornton-Cleveleys, Blackpool, said: "Sadly, I have also had the news that two members of staff from Blackpool schools are currently in ICU [Intensive Care Unit] at Blackpool Victoria Hospital.
"This reminds us how real the threat of Covid can be and how essential it is that we maintain the hand - face - space guidance."
Blackpool Council, which launched a £20,000 PR offensive two months ago in a bid to reassure people classrooms are safe, refused to give an update on the workers' conditions or say which schools they are from.
"We cannot comment on individual cases," a spokeswoman said.
At least 11 local schools, which have remained open during the second lockdown, have been forced to send children into isolation, while at least two have been forced to close completely.
Blackpool's director of public health said recently he agreed with the Government's decision to keep schools open during the second national lockdown, despite lowering the threshold for coronavirus testing.
Dr Arif Rajpura, who two months ago ordered headteachers to send youngsters home to be tested even if they show unofficial mild symptoms such as tiredness or a headache, said: "Considering the detrimental impact of being away from the education system, as well as the low risk of Covid-19 to young people, school is absolutely the best place for children to be."
The National Education Union wanted primary and secondary schools to close their doors to all but vulnerable pupils and the children of key workers during the second national lockdown, like during the first.
In contrast to the NEU's position, the National Association of Headteachers said that it was "right to prioritise keeping pupils in school".
Geoff Barton, the general secretary of the Association of School and College Leaders, agreed that the priority should be for schools to stay open.
But Tina Rothery, co-chairman of the Blackpool and Fylde Green Party, said: "It's becoming increasingly clear that, no matter how much effort our wonderful teachers and staff are putting into keeping schools safe and open, there are growing problems."
The majority of youngsters were off school, learning from home, from March until the end of the summer term.
They returned to the classroom in September.
Earlier this month, tributes were paid to "honest and humble" French teacher and basketball coach Maroun Mourani, who taught at St Edwards College Liverpool.
The 55-year-old was taken to hospital with breathing difficulties "presumed related to Covid" but lost his fight for life, the school said.
