Virulence

Because the potential for a swine flu pandemic is now present, it is helpful to compare the current epidemic with those of earlier periods. The chart below gives figures for either worldwide or the U.S., depending on what figures were available. The most current swine flu epidemic figures are given last and will change constantly, hence the link is given to current data. It is significant that as of April 28, 2009, over 80% of cases and 100% of deaths have been in Mexico. A CNN article entitled "Why only deaths in Mexico?" highlights some questions currently confounding medical researchers.However on April 29, 2009 it was confirmed that a 23-month-old child from Texas was the first fatality from outside Mexico, raising fear that Swine flu could cause a pandemic.

Epidemics Year Infected Deaths Mortality % Death rate/1,000
(avail. data)

Spanish flu 1918-19 1 billion 30 million 3% 30
(worldwide)

Asian flu 1957 45 Million 70,000 16% 1.6
(U.S.)

Hong Kong flu 1968-69 50 million 33,000 .07% .7
(U.S.)

Avian flu 1990-today 421 257 61% 610
worldwide)

SARS 2002-03 8,096 774 9.6% 96
worldwide)

General flu Yearly average 50 million 36,000 .08% .8
(U.S.)[1]

Swine flu as of 4/29/2009[2] 273 153 2.6% 26
(worldwide)
"confirmed"