The US Securities and Exchange Commission has closed an informal investigation into vaccine maker Chiron’s failure to deliver an agreed batch of its flu vaccine, Fluvirin, to the US government in 2004, recommending no enforcement action against the company regarding this matter.

The enquiry was launched after Chiron delivered just 13 million doses of Fluvirin to the USA, falling substantially short of the expected 48-50 million doses following a temporary suspension of manufacturing at its UK plant on the discovery of contaminated batches of the product. This effectively halved the USA’s stockpile, and forced Chiron into restating its second- and third-quarter earnings for 2004.

This is very good news for Chrion, and removes yet another barrier to the planned acquisition of the firm by Swiss pharmaceutical heavyweight Novartis. Just a few days ago, Novartis' proposed $5.1 billion takeover was granted a green light by the European Commission, after already having received clearance by the Federal Trade Commission. The companies expect the deal to close by the end of June.