> Diseases that are endemic today, such as chicken pox, once caused epidemics with massive body counts, notably in North America. No vaccines, no advanced medical care, and no natural immunity meant that some villages just ceased to exist.
You may be confusing chickenpox and smallpox? Chickenpox is generally considered a pretty mild disease (many countries still don't routinely vaccinate against it), and was so historically as the infectiousness ensured essentially everybody would be infected as a child.
WHO guidelines are actually to only vaccinate if rates can be kept above 80% consistently, otherwise it'll likely hit older populations with much more dire consequences.
You may be confusing chickenpox and smallpox? Chickenpox is generally considered a pretty mild disease (many countries still don't routinely vaccinate against it), and was so historically as the infectiousness ensured essentially everybody would be infected as a child.
WHO guidelines are actually to only vaccinate if rates can be kept above 80% consistently, otherwise it'll likely hit older populations with much more dire consequences.