All Nature’s pandemic flu coverage is collected on our news special page.
With flu season looming, crunch-time is rapidly approaching for Northern hemisphere countries’ pandemic planning. It seems likely that the pandemic H1N1 virus will be the predominant strain seen in the upcoming flu season, as data from the Southern hemisphere show that it is out-competing and displacing seasonal strains. The big question mark is when the flu season will start – although some vaccine is already beginning to flow, substantial amounts sufficient to vaccinate large parts of the population won’t become available until October/November onwards.
The pandemic H1N1 virus has continued to circulate out-of-season throughout the summer, and with schools reopening and colder weather on the way, one possibility is that peak flu season may occur as soon as this month, rather than in the more typical mid-winter window. If it does come earlier, countries will be faced with tackling the pandemic with one hand tied behind their backs, as little vaccine would be available.
The challenges of handling the pandemic should not be underestimated. I have an article in this week’s Nature surveying researchers from a selection of countries worldwide, describing the scientific and public-health challenges they face in battling the H1N1 virus – see Pandemic flu: from the front lines . A recurring theme is that even if the severity of the virus remains moderate, public health systems and particularly intensive care units, risk being overwhelmed.
An intensive care doctor in Winnipeg, Anand Kumar, told a two-day conference on the pandemic organized their this week by Canadian health authorities, that the virus is the “most frightening” thing he has seen in his career. (Ottawa Citizen)
“It’s an absolutely massive onslaught of incredibly sick young people that I had never imagined I would see in my life,” Kumar said of his experience treating patients in Winnipeg’s intensive care units. “It’s startling, and more than a little frightening, especially when you don’t know what the ceiling of this is going to be.”
The pathology of the pandemic virus in the lungs of severe cases looks more like the deadly H5N1 than seasonal flu, Sherif Zaki, head of infectious diseases pathology at the U.S. Centers for Disease Control, told the Canadian Press in an article published today. In the same article, Paul Hebert, another intensive care doctor, described how difficult it was to get severe cases enough oxygen: “They have everybody on experimental ventilators and techniques. They can barely keep them alive.” One-third of those who develop pandemic virus-induced acute respiratory distress symptom die.
Some possible good news this week came from a small clinical trial by Novartis which showed that one dose of vaccine was sufficient to provoke an adequate immune response, although two doses was much better. (Reuters). It’s conventional wisdom, and past experience, that whereas seasonal flu only requires a single shot because everyone, except infants, has some preexisting immunity from past exposure to virus, pandemic flu is expected to require two shots, as no-one has any preexisting immunity to the new virus.
If the Novartis results are confirmed, needing just one dose would effectively double the amount of vaccine available, and allow more vaccine to be available sooner (the Chinese company Sinovac last month also said a single dose of its vaccine also worked, but details of that trial are scarce.
However, the Novartis results are not entirely unexpected, as the trial used an adjuvanted vaccine, containing a chemical to boost the immune response. It’s still unknown, whether an unadjuvanted vaccine will need one or two doses – my bet is on the latter. Preliminary data to answer that question should be forthcoming this month from both trials by vaccine makers and a series of trials being done by the US National Institutes of Health – see my interview on this topic with NIAID director Anthony Fauci.
The question is more than academic. The United States, for example, has bought huge stockpiles of adjuvant but seems set to use them with flu vaccines as a last resort. Unlike European countries, it has no past experience of adjuvanted flu vaccines (see Regulators face tough flu-jab choices, US ramps up swine flu protection and Vaccine decisions loom for new flu strain). Conversely, if it confirmed that only one dose of adjuvanted vaccine is needed, but two of non-adjuvanted, that could shift the debate over which type of vaccine to use in the US.
Whether the US uses adjuvants or not will also affect how much vaccine is available for others. If adjuvants are widely used in the US and elsewhere, that would boost the overall amount of vaccine available from existing production capacity and allow orders to be filled more quickly. As matters stand, the combined orders for vaccine by the US and other rich countries, could potentially tie up most of the world’s pandemic vaccine production capacity for 6 months or longer, so depriving other countries of vaccine.
That harsh reality is hitting home, with the media in India criticizing the government for having no vaccine orders in place, and domestic vaccine production not due to come on-stream until next spring. The Times of India says, ’H1N1 vaccine ready, India napping’. The Indian government has responded that it is in discussions with international vaccines makers to carry out clinical trials of the vaccine in India, and to announce its first orders, of undisclosed size, this week for vaccine that would be available in December (a href=”https://www.deccanherald.com/content/22883/2-foreign-firms-ready-try.html”>)Deccan Herald.
For other recent news, see last night’s CDC briefing on cases in children, and a brief update by the WHO on the global situation: ‘Preparing for the second wave: lessons from current outbreaks’.
Posted on behalf of Declan Butler