So....was more science or less science applied to the COVID mRNA vaccines compared with previous vaccine releases?...maybe small pox or mumps (MMR)?
And why are those irradiated....but we still have COVID?
More science. Both the Pfizer and Moderna vaccines ran phase 3 clinical trials with 35,000-40,000 people. That's an unprecedented scale. Most phase 3 trials enroll no more than a couple of thousand. And if you have prescription medicines in your cabinet now, there is a pretty good chance some were approved after testing on fewer than five hundred people.
You can find clinical trial results at
https://clinicaltrials.gov. I studied the EUA submittal documents on that site for both the Pfizer and Moderna vaccines, and I was impressed. They tested on subgroups divided by age, sex, race, ethnicity, obesity, hypertension, diabetes, chronic kidney disease, asthma, chronic lower respiratory diseases, nicotine dependence, substance use disorder, ischaemic heart disease and other forms of heart disease, socioeconomic deprivation, cancer (and haematological cancer in particular), chronic liver disease, stroke, dementia, organ transplant, rheumatoid arthritis, lupus, psoriasis, disorders involving an immune mechanism...over 40 comorbidities in all. I've never seen trials cover so much ground.
Smallpox and mumps are happy cases in that the viruses don't mutate into other virulent forms. The vaccines have evolved and improved over time, but they've only had to target the same old virus. The mumps vaccine still targets the same virus that microbiologist Maurice Hilleman cultured from his daughter's throat in 1963. The virus is named for her; it's the Jeryl Lynn strain.
At the other end of the scale, HIV mutates so rapidly, while retaining virulence, that a successful vaccine has yet to be developed, despite decades of effort.
Flu is somewhere in the middle. It mutates into new, infectious strains, while at the same time known strains become more or less prevalent in Asia, so it's a new challenge every year when flu season arrives in our hemisphere. So the vaccine is a little different every year.
Covid, of course, also mutates. I've not been counting, but the number of identified strains must be in the low dozens by now. Antibodies raised by the vaccines still work against any of them, but with varying degrees of effectiveness.
Pathogens tend to evolve to become more infectious but less deadly over time...that's what success looks like for a virus or bacterium. They can propagate most effectively if they
don't kill their host. Fortunately, Covid is following that pattern. The current strains are much less dangerous than the Covid classic that first arrived on our shores.