H7N9 cases jump, some show resistance to Roche's Tamiflu

The arms race analogy for vaccines is rarely more apt than during a pandemic flu outbreak. Last week the U.S. touted a new, more streamlined approach to vaccine development. This week the virus raised the stakes with a surge of new cases that suggest it is adapting to human hosts.

On Tuesday China reported another 14 H7N9 cases, the biggest jump since the outbreak began. H7N9 has now infected 77 people in China within three weeks, more than H1N1 has managed in a decade. Another two deaths brought the total killed by the virus up to 16 too. One week earlier there were just 24 confirmed infections and seven deaths. The surge in cases came as the virus spread beyond the original epicenter in Shanghai. Last weekend cases were seen in Beijing, 665 miles to the north of Shanghai.

Among the new infections were some mild cases which, counterintuitively, have officials worried. The appearance of less virulent cases suggests the virus is adapting to human hosts, increasing its ability to spread, Nature reports. So far poultry has reportedly caused the infections, but two family clusters suggest limited human-to-human transmission is possible and happening. A mutation to allow the virus to easily spread between humans is one of health authorities' biggest fears.

Another fear is the development of resistance to drugs. And this might already be coming true. A mutation associated with resistance to neuraminidase inhibitors--like Roche's ($RHHBY) Tamiflu and GlaxoSmithKline's ($GSK) Relenza--was found in genetic sequence data from a H7N9 patient specimen. The mutation can be present in viruses sensitive to Tamiflu--and China reports this is the case in H7N9--but it warrants attention. "It's not a strong signal, but there's a possibility [of resistance]," Japanese state health institute director Masato Tashiro told Bloomberg.

- here's Forbes' article
- check out the Nature item
- see Bloomberg's article