Speaking to the BBC’s Andrew Marr Show, the Health Secretary said the majority of sick patients had not been vaccinated but were eligible for one.
Of the 18, he said five patients received one dose of the vaccine, while one person received both injections.
He said Bolton’s figures supported early data suggesting the vaccines were effective against the B.1.617.2 strain of coronavirus – often referred to as the Indian variant.
Mr Hancock said: ‘There are currently 18 people hospitalized with coronavirus in Bolton.
“The majority of these people didn’t get the shot, but are eligible for the shot. “
He added: “We believe there are five people who ended up in the hospital after being hit. This is why it is so important to get the second shot.
“The vast majority didn’t get any hits, but were eligible.
“A small number of them had a stroke and then there was a case where they had two strokes and they ended up in the hospital. They were fragile.
“It all goes to show that the best thing we can do is get the vaccines out, including those second shots.
“In areas where we see an increase in cases, we are launching tests in very large numbers.”
Mr Hancock also revealed that the government would open a new vaccination site in Bolton on Monday and encouraged anyone eligible to ‘come forward’.
A mass vaccination center at Essa Academy in Great Lever drew huge queues on Saturday as a total of 4,000 Pfizer jabs were made available to people who live, work or study in areas of postal code BL3 or BL4.
Cases have skyrocketed in Bolton in recent days, leaving it with the highest infection rate in the country at 254.9 cases per 100,000 population – more than ten times the national average.
Testing has been stepped up as Bolton’s advice aims to track the spread – believed to be due to the B.1.617.2 strain of coronavirus – and ensure those infected isolate themselves.
Council teams hope to distribute test kits to between 10,000 and 12,000 households around areas southwest of the city center this weekend.
Speaking to Sky News’s Sophy Ridge on Sunday earlier today, Mr Hancock said he was ‘not ruling out’ the implementation of another local lockdown in Bolton if one was needed to protect people.
“We have done a huge amount of testing, we have also reinforced that with the army personnel, and we are expanding the vaccination program – especially for those second shots which are the best protection against going back to the hospital.
“So for now we’re taking the approach that has worked in South London – which is this massive surge test – but of course we’re not ruling out further measures.
“Given that Bolton has been in some form of lockdown for a year, this is not a step we want to take but of course we might have to and we will if there is a need to protect people.”