Councillor Shaun Davies said one theory was that areas that previously had lower infection levels were now suffering because they had not built up “community immunity” earlier.
But he said this was one of several possible explanations, and, whatever the reason for the high rate, he urged the population to get tested twice a week, wash their hands regularly and self-isolate when they test positive.
He was speaking at a meeting of the borough’s cabinet.
Telford & Wrekin saw 734 cases reported in the seven days up to September 19, according to the council's latest update.
That gives it a rate of 405 cases per 100,000 people – the eighth highest in England, and the highest in the West Midlands.
Councillor Davies, who heads the borough’s Labour administration, said: “I am concerned that, for the last two weeks, we’ve had the highest Covid rates in the West Midlands.
“There is a huge amount of debate as to why that might be.
"There are some theories around areas that have had lower case numbers, historically, not necessarily having the community immunity, and now in this sort of ‘third wave’ being caught up.
“But I just want to say very publicly that we do need to ensure we continue to redouble our efforts, making sure we get tested at least twice a week, washing your hands regularly and ensuring that we isolate if we test positive for the virus.
“We are looking at ways in which we can support communities further.
“In the past, Government has helped those areas that had high prevalence levels of Covid and we’ll be looking to Government to understand how they will support Telford and Wrekin if that situation continues and deteriorates further.”