The researchers did not find a significant difference in effects from the 1918 and 1930 viruses in infected pigs. This was surprising, since the 1918 virus killed more than 20 million people and was lethal to ferrets, mice and macaques. Another surprising finding from the study was the rapid antibody response in the animals infected with the 1918 virus, which is not typically reported for the swine influenza virus.
This supports the alternate theory that it was not the virus that killed but a co-infection of strep for which we did not have antibiotics in 1918. The strep coinfection would not have occurred in the 1930 cases.
It's been my understanding that viral infections are rarely killers. That the viruses create opportunity for more serious bacterial infections.
I’ve noticed that some sources no longer call it Swine Flu. They call it Influenza A (H1N1)