(Bloomberg) -- The U.K. reported the highest number of Covid-19 deaths since March, prompting a top government health official to warn the pandemic is “not over yet” despite a continued fall in confirmed cases.

There were 23,511 new coronavirus cases recorded on Tuesday, down for a seventh day. But the number of deaths jumped to 131, the most since March 17, according to the latest data.

An increase is consistent with the lag between infections and serious illness from Covid-19, given the U.K. saw a surge in cases driven by the highly transmissible delta variant in June and earlier this month.

“We know deaths follow when there are a high number of cases and data today highlights we are still in the third wave,” Yvonne Doyle, medical director of Public Health England, said in a statement.

Meanwhile senior Cabinet minister Michael Gove criticized people who are still refusing to be vaccinated, and said they could be barred from some events.

‘Selfish’

“Ultimately, if you can be vaccinated and you refuse to, that is a selfish act,” Gove told the PA news agency in Glasgow. “You’re putting other people’s health and lives at risk.”

Just over 70% of U.K. adults have had the two vaccine doses needed for maximum protection, but there are fears not enough young people are coming forward for their shots. Ministers have said people will need to be fully vaccinated to enter nightclubs from the end of September, and could extend this to sports events and concerts.

Officials are also worried that people may relax given the marked decline in U.K. infections in the past week, which has puzzled scientists and raised hopes that the crisis may be coming to an end.

The government has rushed to dampen any celebration, pointing out that the data on daily cases don’t yet reflect the impact of lifting virtually all pandemic restrictions in England on July 19.

‘Very Cautious’

Prime Minister Boris Johnson told broadcasters earlier on Tuesday it is “very, very important that we don’t allow ourselves to run away with premature conclusions” about the decline in new infections.

“People have got to remain very cautious and that remains the approach of the government,” he said.

Falling Covid Cases Are Welcome Surprise for U.K. Scientists

Scientists have cited the recent mini heatwave, start of the school holidays and the end of the soccer European Championship as potential factors for the fall in cases -- alongside the vaccine rollout.

The death figures released Tuesday show it will take some weeks before lower case numbers translate into easing pressure on the National Health Service.

Some 5,918 patients were in U.K. hospitals with Covid-19 as of Monday, up from 4,615 a week earlier.

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