The data are piling in, and it looks like one shot of H1N1 pandemic flu vaccine is enough to protect most healthy adults. And today, the FDA announced it has approved the vaccine.

That’s better news than expected—many experts had predicted two shots would be needed, putting pressure on tight supplies. But there clearly will still not be enough vaccine to go around, particularly in poor countries.

In the US, it is conceivable that high-risk populations like pregnant women might get vaccinated before the flu season hits full force, and most people could ultimately get the shot. That’s because the US has bought billions of dollars of vaccine--a price many countries cannot pay for such a limited commodity. Today the head of the World Health Organization, Margaret Chan, said she expected this “virus of extremes” to cause far more deaths in poor countries than in affluent ones.

The dosage in a single shot is 15 micrograms. But there is a way to bring down the dosage and further stretch the supply—using oil-in-water adjuvants, which have been approved for seasonal flu vaccines in Europe. Glaxo Smith Kline (GSK) recently showed that, with its AS03 adjuvant, a 5.25 microgram dose will protect 98 percent of adults (95 percent of the adults in its trials were protected with unadjuvanted vaccine at a 15 microgram dose). Stretching supplies further, GSK says it plans to sell shots with 3.75 microgram.

That’s a substantial reduction in dosage. But as I report in the latest issue of Nature Medicine, US regulatory authorities have not seemed eager to exercise their option to approve adjuvants in pandemic flu vaccine on an emergency basis—a decision that could have implications for global supply.

What do the recent data and vaccine approval mean for the prospects of using adjuvants in the US? I asked Amesh Adalja, a fellow at the Center for Biosecurity in Pittsburgh, Pennsylvania and a physician at the University of Pittsburgh Medical Center.

“I think the approval means that the pandemic vaccine will not be adjuvanted,” said Adalja.

Nonetheless, clinical trials are on deck at NIH to test adjuvanted vaccine. Adds Adalja: “I think that there is enough clamor about adjuvants that maybe we will see some trials using adjuvanted vaccine. The GSK adjuvant, AS03, can be mixed with some of the other manufacturers' vaccines after production and we might get enough data for an approval (but probably too late for this flu season)."

You can access a great rundown of the new vaccine data by Adalja in his blog posting. Despite the new findings, he is skeptical about whether enough vaccine will be ready, even in affluent countries, by the time the peak of the pandemic is expected to hit.

Posted by Charlotte Schubert at 07:02 PM | Permalink | Comments (0)

US regulators may allow the next generation of vaccines to pass their high bar for approval.

On Wednesday, an advisory committee to the US Food and Drug Administration recommended approval of the cervical cancer vaccine, Cervarix, which contains a new adjuvant-substances that give extra pep to vaccines.

If the agency follows through on the committee’s advice, Cervarix will be the first vaccine approved in the US with an adjuvant other than alum-an adjuvant based on aluminum salts used for more than 60 years. The agency is expected to issue a decision by the end of September.

But the big question is whether the US will consider using adjuvants in pandemic H1N1 flu vaccine, a decision that has serious potential to stretch a limited world-wide supply. A positive decision on Cervarix could change the way the agency perceives adjuvanted H1N1 pandemic flu vaccine, an option that does not seem to be its first-choice, as I report in a recent article on adjuvants in Nature Medicine.

Cervarix, made by Glaxo Smith Kline, has already been approved dozens of countries, as have other vaccines with next-generation adjuvants, including several vaccines for seasonal flu.

European regulators are poised to approve vaccines for pandemic H1N1 flu vaccine containing an oil-in-water adjuvant-the same adjuvant used in seasonal flu shots given safely to millions of people in Europe. But US regulators are widely perceived by public health researchers as much more cautious.

The agency, nonetheless, also gave the green light on Thursday to clinical trials of an adjuvanted hepatitis B vaccine, manufactured by the biotechnology company Dynavax. The FDA had put the trials on hold 18 months ago pending investigation into whether vaccination may have been linked to a rare autoimmune condition that had developed in a trial participant. Now the company can continue to test its vaccine in people with chronic kidney disease who do not respond well to the standard hepatitis B shot.

So, it’s been a good week for adjuvants at the US FDA. We will see what that means ultimately for pandemic flu shots.

Researchers at Novartis are still awaiting data on the degree to which adjuvants can cut down the dosage of pandemic H1N1 vaccine. Meanwhile, studies out Thursday in the New England Journal of Medicine suggest that one shot of vaccine may be sufficient. And this Friday the NIH will also discuss early results from its clinical trials. Stay tuned.

Posted by Charlotte Schubert at 04:20 AM | Permalink | Comments (0)

There may be no rhyme or reason to why the H1N1 swine flu emerged as a global threat last spring... but some doctors and health officials are using rhythm to explain how to best avoid this nasty virus.

The US government is asking the public to vote on their favorite H1N1 public service announcement. And while some rappers might want you to throw your hands in the air and 'wave'em like you just don't care', at least one hopeful contestant, Dr. Clarke, is hoping to you'll throw your hands into the sink and start washing them. He already is gaining a bit of a following.

To see all the videos up for vote, click here.

Meanwhile, a cartoon aired at the Shanghai airport has also put the dangers of H1N1 into a rap. To see a capture of the video, click here.

Have you seen any other H1N1 flu raps out there that strike your fancy?

Posted by Roxanne Khamsi at 11:30 AM | Permalink | Comments (0)

Swine flu is entering the mixing bowl. The virus that emerged this spring in Mexico is now reaching the place where it may have its greatest potential to mutate—the tropics. Cases have recently been identified in India, Vietnam and the Philippines.

Flu viruses circulate year-round in tropical regions, where they can mix with each other, mutate and spawn new strains. Two studies published last year outlined this process, showing how seasonal flu strains in the temperate regions originate in tropical regions.

Unfortunately, as Declan Butler at Nature reports, surveillance networks are often weak in tropical countries, so it may be difficult to monitor the evolutionary trajectory of the new H1N1 virus.

Vaccine experts breathed a sigh of relief when the first sequences of the new H1N1 virus revealed relatively little variability among isolates. That makes it easier for manufacturers to produce a vaccine that could work against all forms of the virus. But the virus may surprise us in the fall, popping up as a different sort of beast—or beasts.

There are also fears that the virus will wreak havoc in sub-Saharan Africa, where there are many people living with HIV, weakening their immune system and possibly increasing their vulnerability to swine flu.

Posted by Charlotte Schubert at 02:43 PM | Permalink | Comments (1)