Here are a few thoughts that may help shape your opinion. Remember that any virus can be serious because we dont have significant anti-viral drugs like we do anti-biotics for bacterial infections. Heres a link to Virology on the recent outbreak in Mexico".Influenza incidence is difficult to determine because most infections are not confirmed by laboratory tests. Consequently case estimates play an important role in understanding transmission and spread. In this study, the authors used mathematical models to calculate the number of infections in Mexico based on exportation of the disease by travelers. They estimate that 23,000 infections had occurred in the country by late April. From this number they calculated a case fatality ratio of 0.4%. I note that my own crude calculations yielded a similar number." The CDC reports that the current fatality from infection rate in the US is approximately 5%.
Heres a good look at the potential threat from Global Security.org. which looks at the H1N1 (swine flu...sorry, shouldnt call it that) and the H5N1(avian flu)
"Pandemic years are associated with many more cases of influenza and a higher case fatality rate than that seen in seasonal flu outbreaks. It is common to encounter clinical attack rate ranges for seasonal flu of 5% to 15% in the literature. For pandemic flu, clinical attack rates are reported in the range of 25% to 50%.
During a typical year in the United States, 30,000 to 50,000 persons die as a result of influenza viral infection. Frequently cited numbers are 20,000 deaths each year, and 37,000 annual deaths. About 5-10% of hospitalizations for influenza lead to fatal outcome in adults.
In normal years, although most influenza infection is in children, the serious morbidity and mortality is almost entirely among elderly people with underlying chronic disease. During influenza epidemics from 1979–80 through 2000–01, the estimated overall number of influenza-associated hospitalizations in the United States ranged from approximately 54,000 to 430,000/epidemic. An average of approximately 226,000 influenza-related excess hospitalizations occurred per year, with 63% of all hospitalizations occurring among persons aged > 65 years."
In a nut shell.....if either virus develops significant pathogenic variables then we could be in for a BIG problem. That said , it hasn't and dare I say...probably won't do that anytime soon. As I am fond of saying...probably my microbiology and infectious disease training...It wont be the bombs but the bugs that get us.