Outbreaks of a deadly strain of flu have claimed the lives of elderly people in care homes across the country in recent weeks.

The flu is type A, the most dangerous form of the virus and the strain is H3N2. B and C types of flu generally give less cause for concern.

Health officials say the death rate in care homes is the highest they have seen for several years. In one care home in the south of England, earlier this month, six elderly people died in a matter of days.

“We have had problems in care homes for elderly people and we have seen a few outbreaks with quite high mortality rates since the beginning of December,” said Professor Nick Phin of the Health Protection Agency. “We are more concerned about flu A because it can cause epidemics and pandemics. It also causes more serious illness.”

“We have been getting outbreaks involving 20 to 30 people at a time. When this happens local health protection unit staff go into the homes and take swabs,” added Professor Phin.

“There is a mandatory scheme whereby anyone admitted to a hospital intensive care unit who dies from flu is reported to the Department of Health. But we don’t formally record flu deaths of people dying in care homes. If we get confirmation of flu A from swabs then we can calculate on the balance of probabilities how many deaths in the home are likely to be caused by this strain of flu.”

According to HPA figures there have been 70 cases of type A flu in care homes since November, with the second highest number occurring in schools, with 40 cases. There have been far fewer cases diagnosed in hospitals, with 15 cases diagnosed between December and March.

Professor Phin said that when these outbreaks occurred health officials tackled them vigorously even if only a couple of cases had been identified. In these cases everyone with symptoms is offered Tamiflu and anti-viral prophylactics.

There is a national vaccination programme for flu but these outbreaks have come late in the season and the vaccine administered in the autumn of 2011 has begun to lose its efficacy, especially in older people. The Health Protection Agency tests for the two most dangerous types of flu, A and B. It does not test for type C – the mildest form. In general, cases of flu this winter have been very low with less than 30 GP consultations per thousand involving flu. The outbreak involving deaths in care homes has bucked the trend.

An HPA spokesperson said: “Flu has circulated late this season. Although we have seen a number of flu outbreaks across the UK, the overall current flu activity is low, and has been low throughout the season. There are HPA guidelines in place, which care homes, schools and other sites can refer to should they experience an outbreak of flu.

“The most common flu strain we are currently seeing circulate this season is H3N2, which can cause more severe illness particularly in older people.

“It is very important to remember all those in a clinical ‘at risk group’ should get vaccinated before the next flu season in order to protect against flu strains that will circulate during the winter months. It is also important to practice simple hygiene measures too, such as hand-washing and covering your mouth and nose when you cough or sneeze as to reduce the spread of infection.”