ResearchBlogging.orgA year has passed since the first cases of Influenza A H1N1 in Mexico, we had over 18000 deaths confirmed by lab diagnosis and reported to WHO. Surely an underestimate of the total number of cases.

The average mortality was of 0.5% of the confirmed cases, close to the seasonal flu. The mortality values varied a lot from country to country, and inside a country they varied according to different studies, which show the evident necessity of more available tests and a mutual opinion on the measure to be adopted.

Different from the seasonal flu, over 90% of deaths are concentrated in people younger than 65 yeas old, consequence of the previous immunity older people have. Pregnant ladies were also the most affected, although they represent only 1 to 2% of the general population, they were 6 to 10% of the deaths caused by the flu. Other groups also have their immune systems altered like the obese and the immunocompromised and are also among the most susceptible ones.


Although bearing the already reported drug resistance to adamantanes drug family, the Influenza of swine origin can be treated with sialidase inhibitors, the drugs Oseltamivir and Zanamivir. Oseltamivir, available to be taken orally is cheaper, is still a very effective treatment, reducing the symptom’s severity and the time of hospitalization.

Some resistance cases were found, the majority isolated cases and in patients with treatment flaw mainly of them with prolonged therapy. Rarely patients without history of contact with the drugs were found with resistant viruses; the transmission of this kind of virus was also confirmed.


It is still very hard to diagnose the Influenza virus as a whole. The main method, the RT-PCR technique (virus genetic material amplification) still depends on recent technology and restricted access to poorer areas. We also depend on samples collected during the period of infection. We still need cheaper and more accessible ways of detecting the virus, as well as different and cheaper ways of treatment.

Influenza A H1N1 seems to become a seasonal virus with symptoms and cases like the common flu, however the virus evolutive course is unpredictable. The prevention and survey set for the Avian Influenza and the “normal” virulence of this virus contributed for the Swine Flu not have caused bigger damage. But we are still far from being protected from more pathogenic strains, in case some of them are transmitted more easily.

Writing Committee of the WHO Consultation on Clinical Aspects of Pandemic (H1N1) 2009 Influenza, Bautista E, Chotpitayasunondh T, Gao Z, Harper SA, Shaw M, Uyeki TM, Zaki SR, Hayden FG, Hui DS, Kettner JD, Kumar A, Lim M, Shindo N, Penn C, & Nicholson KG (2010). Clinical aspects of pandemic 2009 influenza A (H1N1) virus infection. The New England journal of medicine, 362 (18), 1708-19 PMID: 20445182