Influenza cases are starting to drop after exceeding a high-alert level for the past four weeks, according to the chief medical officer at the Ministry of Health.

Cheryl Peek-Ball said that although the decline was expected for this time of year, this flu season had peaked unusually late and affected more young people compared with the past five years.

“For the whole population, the five-year baseline average of what we would have had in the month of April has been well exceeded,” Dr Peek-Ball told The Royal Gazette.

“It does appear that influenza cases are starting to decrease, as are the reports of respiratory symptoms generally, and we would expect that at this point.”

Dr Peek-Ball said there were 11 fewer cases of the flu this week compared with last week.

But she added: “This is quite a unique season in that it is a very late peak; to have this happening in April is not typical.”

Nurse epidemiologist Jennifer Wilson said this had also been the case in the United States, although their flu season peaked slightly earlier, and in the UK.

According to Dr Peek-Ball, the flu season normally peaks in January in Bermuda and resolves by about the end of March or early April.

“Surveillance is impacted by many factors, so it’s certainly impossible for me to put an explanation on this but it is an unusually late peak in influenza in this part of the world,” she said.

This year’s flu season has also seen more cases of severe infection in a slightly younger demographic than in previous years, she said.

“The average age for us in this community is 32 years. That’s what’s happened this season and strikes me as younger than typical,” she added.

Dr Peek-Ball said that all cases tested, to the knowledge of the Epidemiology and Surveillance Unit, had shown the presence of influenza A subtype H1N1. she added: “That, too, is not a surprise because that has been the predominant subtype circulating in North America and the UK.

“It is very important that people understand that it is not the same thing as the flu that originates from certain animals and that were novel when they appeared sporadically in humans.”

Dr Peek-Ball also stressed that reports of pneumonia — an infection of the lungs that can be caused by the flu virus or other organisms — received by the ESU had not been unusual.

“Despite the frequent questions about pneumonia, we haven’t had anything out of the ordinary in the way of occurrences, but we’re talking about population numbers and not how many cases there were in any given environment.”

This year, six cases of pneumonia have been reported to the ESU, compared to six last year, 15 in 2014 and 11 in 2013.

But Dr Peek-Ball said not all cases were reported, so the numbers did not necessarily reflect exactly what was happening in the community.

“Surveillance formally counts cases by a strict case definition and recognises that the cases that come to that level of being aware of are many times smaller than the actual number of cases in the community,” she added. “It’s the tip of the iceberg that comes to the Epi Surveillance Unit.”

The ESU receives reports from the hospital, laboratories and physicians’ offices that follow an international standard for reporting diseases.

It releases reports on a weekly basis, but there can be a delay in reporting because instances of disease have to be recorded through the appropriate channels.

There are also privacy concerns, which mean the ESU will not release information about specific cases.

“It is proper public health practice to assure that cases aren’t identified and that people are confident in reporting to us,” Dr Peek-Ball said. “So we do try to honour the privacy and confidentiality.”