SAN DIEGO – Predictions at the International Conference on Antimicrobials and Chemotherapy and the International Congress of Chemotherapy (ICAAC/ICC) 2015 annual meeting tend to be of the dire sort, warning of a return to the pre-penicillin era. So it was a pleasant exception to listen to Glaxosmithkline plc's Rino Rappuoli brim with optimism during his plenary talk on challenges and opportunities of vaccines.

Rappuoli, chief scientist at GSK vaccines, told his audience there is currently "an explosion" of new technologies that will allow vaccines to be made for diseases that have so far resisted those efforts. "I believe that we will see a revolution in vaccines over the next decade," he said.

The new techniques also have the potential to improve current vaccines – specifically, the influenza vaccine, whose production time could be cut from months to weeks through the use of reverse vaccinology.

Rappuoli published proof of principle for the approach, which developed while at Novartis AG, and together Synthetic Genomics Inc.'s co-founder, Craig Venter, in 2013 using the H7N9 strain of influenza. H7N9 was first identified in 2013. To date there have been three waves of infection with a total of 677 cases leading to 2,275 deaths in three years. The virus currently present in 17 provinces in China.

H7N9 is unique among avian influenza virus in having some ferret airborne transmission, albeit inefficiently. Such ferret airborne transmission is indicative of the ability to transmit from human to human. This ability is part of what gives the virus pandemic potential.

When the virus was first identified as a novel influenza strain in 2013, the Chinese Center for Disease Control and Prevention published the gene sequence of its hemagglutinin and neuraminidase – two proteins that are the major determinants of the flu virus' interaction with the cells it infects, and the "H" and "N" in the naming scheme for influenza viruses.

The scientists were able to produce RNA for the protein using the published sequences, a feat that Rappuoli described in his talk as "basically teleporting the organism."

Using synthetic vaccine technology, the team was able to generate a candidate vaccine within eight days. Mice vaccinated with the experimental vaccine had protective antibody titers two weeks after being vaccinated.

"We had a vaccine before the wild-type virus had reached the CDC," Rappuoli said. "This gives you an idea of what kind of game-changer this could be."

H7N9 was the top contender for a problematic flu strain in a talk given by the University of Hong Kong's Malik Peiris, who gave an overview of avian influenza strains that could be candidates for such a pandemic in a session on emerging viral respiratory pathogens.

"H7N9 virus is really catching on, and will soon surpass H5N1," the virus that had the public's attention Peiris predicted.

Its life these days is away from the headlines, but H5N1 is still around. Peiris noted that there is an H5N1 outbreak currently going on in Nigeria, and there were a large number of cases in Egypt last year. Overall, the WHO has reported 844 cases of human H5N1 infections in 16 countries, resulting in 449 deaths.

The mortality rate reported by the WHO necessarily overstates the true fatality rate, since for every case that comes to the attention of the WHO, there are 100 to 500 symptomatic cases and an unknown number of asymptomatic ones. Nevertheless, Peiris estimated that an H7N9 pandemic would lead to 10 to 100 times as many fatalities as the 2009 H1N1 pandemic.

H7N9 is much more transmissible from poultry to humans than H5N1, and Peiris predicted it will "spill over from China into Vietnam, and further on from there."

Calling the flu an emerging respiratory pathogen gets to the heart of influenza's paradox. In one sense it is not an emerging pathogen at all, arriving yearly like unwelcome relatives for a holiday. Peiris told the audience that "the ecology of influenza is much wider" than the strains that are most likely to cause human infections such as H1N1 (which was responsible for the 2009 pandemic), H3N2, H1N2, and H2N2.

Avian influenza strains have their natural reservoir in aquatic birds. But the virus can also establish reservoirs in terrestrial fowl, pigs, horses and other animals.

The flu virus' annual conquest of the globe is sobering to contemplate, and the 2009 epidemic gives a stark example of the need for the sorts of technologies Rappuoli described. Peiris pointed out that the 2009 pandemic strain arose in Mexico in the spring. By September, 30 percent of children in Hong Kong were infected.