[lamontcg]

Thing is though that the RotaShield case highlights that vaccines either cause side effects with 3 months or they do not:

> The results of the investigations showed that RotaShield® vaccine caused intussusception in some healthy infants younger than 12 months of age who normally would be at low risk for this condition. The risk of intussusception increased 20 to 30 times over the expected risk for children of this age group within 2 weeks following the first dose of RotaShield® vaccine. The risk increased 3 to 7 times over the expected risk for this age group within two weeks after the second dose of RotaShield® vaccine. There was no increase in the risk of intussusception following the third dose of RotaShield® vaccine, or when three weeks had passed following any dose of the vaccine.

It didn't affect them 5 years later, it happened 2 weeks after the vaccine.

This is typical, and why it isn't particularly necessary to do safety studies of vaccines longer than 3-6 months.

You can argue that the safety study failed in that case and wasn't broad enough and the side effect wasn't noticed so that it wasn't approved, but it was found very quickly after approval, and the rate was 1 in 12,000 vaccinated infants. That is difficult statistically to find in studies of only 25,000 individuals.

And we've had a massive "phase 4" trial of mRNA vaccines involving >100M individuals that has gone on for months now. We know they're incredibly safe.