We are 2 months into the outbreak with H1N1 (swine) influenza, a variant not previously identified in humans. However, data suggest it was circulating unnoticed in pigs for years. It has two characteristics of concern: it spreads from person to person a bit more readily than older flu strains, and it seems to keep on spreading through the warmer months. This is likely due to the large number of susceptible people in the population, since it seems that younger people have little "crossover" immunity from exposure to previous flu strains, while the oldies appear to have partial immunity, based on the pattern of spread. These features might be seen with any strain arising de novo (not derived from recently circulating human strains).
Recent research suggests that, in terms of a repeat of the 1918 flu, we have less to be worried about than has been thought. These studies note that an estimated 95% of deaths from the 1918 pandemic occurred as a result of complicating, secondary illnesses that developed in people weakened by the flu, rather than by the flu itself. Furthermore, this analysis suggests that by preventing and/or treating such secondary illnesses, many lives could be saved.
Brundage et al.'s abstract notes that this "hypothesis suggests opportunities for prevention and treatment during the next pandemic (e.g., with bacterial vaccines and antimicrobial drugs [antibiotics]), particularly if a pandemic strain-specific vaccine is unavailable or inaccessible to isolated, crowded, or medically underserved populations."
CDC posts an H1N1 Flu Situation Update at least weekly. As of June 19, there were 21,449 "confirmed or probable" cases in the US and 87 deaths, or 1 death per 250 cases. It is great that CDC is keeping such close track of things. But what are they doing with this information, in terms of analyzing how many people died from secondary infections, what complications might lead to death, and which patients are most at risk and need special care. Most importantly, what do the data tell me can be done to prevent my patients from dying?
Unfortunately, the expert advice needed is MIA. CDC's "Interim Guidance for Clinicians on Identifying and Caring for Patients" with H1N1 flu was written on May 4, when there were just a few cases in the US. CDC has yet to update it with information from the 20,000 cases diagnosed since then. Instead, the (old) website says, "There is insufficient information to date about clinical complications of this novel influenza A (H1N1)..."
The only treatments and preventives recommended are Tamiflu and Relenza, even though CDC still fails to provide any information on how well or poorly they affect the clinical course of the illness. Meantime, CDC suggests that longstanding guidelines for the treatment of community acquired pneumonias could be followed for secondary infections. The link they provide did not work for me. And anyway, I know the guidelines. What I need to know is whether this advice is the best possible in patients with H1N1 flu.
On May 17, Australia moved to a new national health alert level, called “protect,” to focus on the early treatment of those vulnerable to [severe illness from] the flu, including pregnant women, people with respiratory disease, heart disease, diabetes and obesity. And on July 2, Australia's Health Minister, Nicola Roxon, reassured parents that swine flu does not pose a greater danger to children than seasonal flu.
CDC, wake up!