I'm a bit confused about claims that the 1957-1958 influenza pandemic (Asian Flu) was deadlier than Covid-19. It 's not what the statistics suggest.
The case mortality rate in the UK was 0.3%. The case mortality rate for Covid-19 isn't known yet, but it's estimated to be between 0.5 and 1%. That figure will possibly go down as more younger people are infected and recover, but it's not going to be lower. An estimated 3% of cases of Asian Flu had complications, which is probably about the same as Covid-19.
33,000 people in the UK died from Asian Flu. That figure has already been exceeded for Covid-19 and will certainly increase.
A vaccine was found for Asian Flu, which helped prevent cases. It also causes bacterial infections, which were controlled with antibiotics.