Naming 5 would be too short, it's actually the contrary, most countries do NOT have a functional vaccine monitoring system, so the shorter list would be the countries that DO. WHO's GVSB says it too, 65% of member states "do not have a functional post-marketing monitoring system" for vaccines. But since you asked: Philippines, India, Pakistan, Indonesia, Nigeria, Bangladesh, that's ~+2 billion people right there but I can also tell you from European country from my own family (you can discard, sure) that they never actually reported anything despite having patients that complained of X, but that's anectodal, but what I'm saying regarding the fact that it's not reported isn't, it's data, available publicly. My own kid's Pedia do not report as well.

To your second question: many do have drug reporting on paper, mostly because GAVI requires an AEFI committee to access vaccine funding but in practice it's not the case which is why I said "(or just wouldn't do it)", virtually no Pedia would write a report for a kid having a headache post vaccination. As of 2022, apparently only 43% of ALL countries met WHO's absolute minimal bar of ONE serious report per million people per year, SE Asia is at 9%, a third of countries report close to zero.

And this isn't bad faith on my part, these are WHO and CDC's own numbers, not an opinion.

[1] https://www.who.int/docs/default-source/documents/global-vac... [2] https://iris.who.int/bitstream/handle/10665/70854/WHO_IVB_12... [3] https://www.cdc.gov/mmwr/volumes/72/wr/mm7249a2.htm [4] https://pmc.ncbi.nlm.nih.gov/articles/PMC5857292/ [5] https://www.gavi.org/sites/default/files/sites/default/files... [6] https://www.fda.gov.ph/pharmacovigilance/ [7] https://link.springer.com/article/10.1007/s40801-025-00492-z [8] https://siapsprogram.org/wp-content/uploads/2016/03/15-125-P...