Vaccine makers praised the U.S. response to the swine flupandemic on Wednesday but said regulatory delays and public suspicion have held up innovative ways to speed and stretch the U.S. influenza vaccine supply.

Pharmaceutical executives said their companies were working on ways to make flu vaccines more quickly and in greater quantities, but said regulatory approval was slow. They complained about U.S. reluctance to use additives called adjuvants that can boost a vaccine's effects.

The pandemic of H1N1 swine flu has infected 22 million Americans and killed 3,900, according to the U.S. Centers for Disease Control and Prevention. Some politicians have criticized the U.S. response but the executives and other experts defended the government at a joint hearing of House of Representatives subcommittees on health and oversight.

We have moved as fast as or faster than any other country in the world, said Jeffrey Levi, executive director of the non-profit Trust for America's Health, which has in the past criticized U.S. preparedness for pandemics.

Given the totality of circumstances, the successful development, clinical testing, and large scale production of an H1N1 vaccine in such a short amount of time, despite all the challenges and uncertainties that were overcome, was a significant accomplishment for the U.S. government and Novartis Vaccines partnership, added Dr Vas Narasimhan of Novartis.

But they also pointed to longstanding roadblocks to moving beyond old technology that relies on chicken eggs to more reliable biotechnology methods that use cells.

In the current environment, the hurdles to bringing forward innovative products like cell culture-produced live, attenuated influenza vaccines are likely to take many years and cost a great deal, said Ben Machielse of AstraZeneca unit MedImmune.

Manufacturers urgently need a way to discuss end-to-end product development plans with the FDA (U.S. Food and Drug Administration) or its advisory boards early in the product development process, Machielse said.

FDA's Dr Jesse Goodman said the agency was sticking with tried and true technology and Levi said officials had little choice, given the U.S. public's mistrust of new vaccines.

MedImmune has not had the problems with making vaccines that other manufacturers did and has more vaccine than it can package in the approved nose sprayers. The company and FDA been discussing using nose droppers as an alternative.

DELAYS AND RULES

We proposed an aggressive schedule to deliver 30 to 50 million more doses in October, Machielse said in written testimony. But he said the Health and Human Services Department delayed consideration when it was learned that a single dose of H1N1 vaccine would protect adults and older children.

Phil Hosbach of Sanofi Pasteur Inc said HHS ordered more pre-filled syringes and fewer multi-dose vials of vaccine than the company had anticipated, forcing time-consuming changes.

Another problem -- Americans do not seek flu vaccines in general. Only 107 million got seasonal flu vaccines in 2007, said Narasimhan.

U.S. seasonal influenza manufacturing at 2008/2009 pricing levels was not profitable, Narasimhan said.

This situation, combined with ever-increasing regulatory requirements and additional data requirements for the licensure of new and improved influenza vaccine products, means that many improvements ... are not being pursued.

For instance, adding adjuvants would help by allowing lower doses of vaccine and potentially offering cross-protection against mutated versions of flu viruses, Narasimhan said.

But he said there was no clear regulatory pathway for adjuvants in the United States, although they are widely used in Europe. And Levi noted that Americans are afraid of new ingredients such as adjuvants.

An estimated 159 million Americans such as pregnant women and healthcare workers have priority for vaccine, and surveys suggest about half would seek one.

HHS had hoped to have vaccinated most of these people by the first week of December but the CDC's Dr Anne Schuchat said 49 million doses had been delivered as of Wednesday.

Medicine