Allen & Overy (A&O) has secured enough drugs to treat its entire staff for swine flu, it has emerged, as the World Health Authority (WHO) this week officially classified the outbreak as a pandemic.

A&O ordered the stocks of the anti-viral drug Tamiflu – the primary means to treat the new strain of flu – several years ago as part of its business continuity planning as the drug has broad applications for viral infections.

A&O has enough of the drug to treat its entire staff and is holding the drugs locally across its global network through third-party medical providers, with the exception of jurisdictions where local regulations restrict such a policy.

A spokesperson for the firm told Legal Week: "This provision forms part of our business continuity planning, which includes a number of different contingency plans and measures to ensure we are as prepared as we can be for all eventualities that could impact our operations.

"Since the issue of swine flu emerged we have kept our people informed of the latest advice and guidance from the WHO and other organisations and issued updates to them as and when appropriate as the situation developed globally."

The news comes as the WHO on Thursday (11 June) as expected raised its global alert level for the disease from five to six, the first official flu pandemic for 40 years.

The disease has so far been confirmed in more than 27,000 cases worldwide – including 822 cases in the UK – after initially emerging in Mexico, though the strain has so far proved less severe than initially feared.

Meanwhile, it emerged today (12 June) that Lovells' Hong Kong office had been affected by the disease after an attendee to a local student day tested positive for the flu strain.

The firm's office was cleaned after local health authorities were contacted and staff members involved have been quarantined. One staff member has subsequently fallen ill with the virus.

A Lovells spokesperson commented: "In London we have a small working group that has looked at some of the implications of an outbreak and have also been working with our occupational health advisers to plan what we might do in the event of having a case, but first and foremost we follow the appropriate health authority guidelines.

"We also have substantial stocks of Tamiflu, but since it requires a doctor's prescription before it can be administered we cannot simply hand it out. We would not expect to be a primary dispenser of the drug since that is the role of the health authorities but we do have a supply as a reserve contingency."

Many law firms are currently reviewing their policies to respond to the disease.

Clifford Chance (CC) has formed a taskforce to stay on top of developments on the spread of the virus and has provided staff with guidelines on what to do should they believe they have been affected.

CC has also increased the levels in which high traffic areas of their offices are cleaned and is advising staff to rethink travel to Mexico.

Norton Rose said it has been following the development of swine flu and has sought independent medical advice from health officials who deal with crisis management during the rapid spread of a virus.

A&O has stopped staff travel to Hong Kong, while Herbert Smith handed out facemasks to staff travelling to the region.