Adults must consider their behaviour coming into winter – with countries facing a stark choice between keeping children in school or bars and nightclubs open, a global health expert has warned.

Infection will grow “no question” in Europe as people move back indoors in the coming months and the continent is facing “that moment” where big decisions will have to be made, Dr Michael Ryan, executive director of the World Health Organisation (WHO) Health Emergencies Programme said.

He said two priorities have seemingly been agreed globally – protecting the older and vulnerable populations who are most at risk, and ensuring children continue to get an education.

Addressing a WHO press briefing on Tuesday, he said: “How do we hold those two principles – protecting the vulnerable from death, getting our children back to school? Something, in some sense, has to give.”

He said adults must “separate themselves enough to drive transmission downwards”.

He added: “So, what is more important, our children back at school or the nightclubs and the bars open? And I think these are decisions that we have to make coming into the winter months.

“These are trade-offs, there are no easy answers.”

He praised teachers and administrators around the world for their “huge efforts” to get children back to school, but said the rest of the population must support that work in their own behaviour.

He said: “The best thing we can do to support our children back in school is reduce our risk of being exposed and reduce our chance of exposing others.

“If we do that our children can stay in school.”

He repeated WHO director-general Tedros Adhanom Ghebreyesus’ remarks from a day earlier on countries’ essential priorities including sustained surveillance of the virus, testing and tracing, cases isolating and contacts quarantining.

Dr Ryan acknowledged that “it’s not easy and it’s hard to sustain and everyone is exhausted”, but insisted “there are no alternatives”.

He added: “There are no magic bullets, I’ve said it before. And we need to stop looking for unicorns.”

Opening the briefing, Dr Tedros said school closures must be a “last resort”.

He said: “Given the devastating consequences on children, youth and our societies as a whole, the decision to close schools should be a last resort, temporary and only at a local level in areas with intense transmission.”