Flu can kill. Any effort to limit its impact through mass immunisation is therefore a matter of life and death. Against this background, inspectors from the Medicines and Health Products Regulatory Authority (MHRA), fearing possible contamination in a small number of batches of vaccine, have suspended the US-based Chiron drugs firm’s licence to produce the vaccine at its plant in Speke, Liverpool.

The MHRA was in an unenviable position, but one largely of its own making. It was forced to weigh the risks of major flu outbreaks because of low vaccine stocks in the UK and, especially, in the US, where Chiron sells most of the Speke plant’s output, against those of permitting the distribution of contaminated vaccine. In the circumstances it made the right decision, yet those circumstances could and should have been avoided.

Regulators knew of potential problems at the Chiron plant well before Tuesday’s announcement by the MHRA, whose effect has been to rule out any flu vaccine production there for the forthcoming flu season. British suppliers must find more than two million doses elsewhere as a result. The US must find 46 million-48 million — a daunting shortfall that has forced public health officials there to plead with the able-bodied to forgo vaccinations this winter to ensure that those most in need are protected.

The risk of such a crisis was discussed but largely discounted in Congress last week, when Howard Pien, Chiron’s chief executive, acknowledged difficulties but told a special Senate committee he was confident that the Speke plant could still meet its commitments to US customers. By this time, according to the Department of Health, British inspectors already knew of what they considered to be further problems at the plant. But not only were US officials apparently not alerted to them; the British flu vaccination campaign was allowed to proceed in the full knowledge that a major supplier was about to be barred from production.

Fortunately for British pensioners and others for whom flu poses a greater-than-average risk, Chiron produces a fraction of the UK’s flu vaccine, and back-up plans were in place to make up the domestic shortfall. Even so, the timing of Tuesday’s announcement could hardly have been worse. It came as the yearly drive to increase uptake of flu vaccines was supposed to be hitting its stride, and at a time when public confidence in vaccination campaigns is at an all-time low after the MMR controversy and the inadequate public consultation that preceded the launch of the new five-in-one vaccination for babies. That the plant itself, under different ownership, has been previously dragged into controversy over government smallpox vaccine contracts will do little to bolster that confidence.

Britons must now take on trust the quality of the flu vaccines being found for them, but they are right to question whether the Chiron problem has been handled astutely by the MHRA. Public confidence in the medical system is vital for its own health.

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