Health workers in Hanoi are tightening control over new cases of influenza at 17 hospitals in the city in order to prevent the spread of a newly identified swine flu variant, S-OtrH3N2.

Nguyen Nhat Cam, Deputy Director of the Hanoi Centre for Preventive Medicine, said close attention would be paid to all cases that with flu-like symptoms, as well as serious pneumonia cases.

Cam confirmed that to date Hanoi has yet to detect any cases of the new strain.

Stricter controls will be put into place at airports in order to detect and quarantine any suspected flu carriers. This will include scrutinising those who come from areas with a high infection rate and those who have a fever or other symptoms.

According to Cam, the groups at the highest risk are the elderly, children, pregnant women and people with chronic diseases. It is recommended that they get vaccinated.

The Vietnamese Ministry of Health asked epidemic prevention institutes to prepare to deal with the new strain after three more cases were detected in the US on November 23.

The S-OtrH3N2 virus is a combination of two subtypes of influenza A virus, H1N1 and H3N2,  found in pigs.