AstraZeneca is the latest company to confirm that it is in talks with the health authorities in the USA about developing a vaccine for swine flu.

The Anglo-Swedish drugmaker’s MedImmune subsidiary is “in close contact with the US Centre for Disease Control and Prevention” about using FluMist nasal spray as the basis for a vaccine to combat the latest strain of swine flu, according to Simon Lowth, AstraZeneca’s finance director. However he warned that even if it was decided that a jab was required, it could be months before a vaccine was developed. The firm’s scientists “will need to get feedback and then they will need to deliver a vaccine," he added.

AstraZeneca’s declarations came after Sanofi-Aventis’ chief executive Chris Viehbacher said "we have given our full commitment to healthcare authorities that we’ll do whatever is necessary to help fight a pandemic if it should occur." The company said the World Health Organisation's recent decision to raise its pandemic alert level triggered the next steps in sanofi-aventis' pandemic preparedness plans.

The French drugmaker’s Sanofi Pasteur unit will continue to manufacture seasonal influenza vaccines, but “if someone asked us to change our production...all our teams are on full alert and working to do that," Mr Viehbacher said. However, he acknowledged that concentrating solely on a vaccine against the new H1N1 strain "will be a very difficult choice" because if the pandemic doesn't actually occur, “we could end up with no seasonal influenza vaccine."

Meantime the European Union Health Commissioner Androulla Vassiliou has said that a possible swine flu pandemic would not necessarily cause widespread deaths. Speaking after an emergency meeting of health ministers, she said Europe was well prepared and there was "no need to panic", adding that “we are worried, but we are on top of things".

She added: "The fact that we have been preparing ourselves in the EU for an event such as this for some years now, and the experience gained so far, puts us in a much stronger position." None of the cases of swine flu reported in Europe so far has been severe.

The WHO has said it has no immediate plans for a further rise in the level of alert and its assistant director-general Keiji Fukuda said that “we do not have any evidence to suggest that we should move to phase six”. The latest reports coming from Mexico this morning, the country at the centre of the crisis, suggest that the number of new cases has flattened out along with the death rate.