30% ????? Did you mean in the early 1800s?
"During the 1970s, one vaccine was eliminated. Because of successful eradication efforts,
the smallpox vaccine was no longer recommended for use after 1972. While vaccine research continued, new vaccines were not introduced during the 1970s."
It seems like there was a safety standard back then. Maybe I've missed your research on smallpox. Please enlighten me.
Here is research from NIH:
"ADVERSE EFFECTS OF VACCINATION
Frequency and Clinical Features
Smallpox vaccine is less safe than other vaccines routinely used today. The vaccine is associated with known adverse effects that range from mild to severe. Mild vaccine reactions include formation of satellite lesions, fever, muscle aches, regional lymphadenopathy, fatigue, headache, nausea, rashes, and soreness at the vaccination site. A recent clinical trial reported that more than one-third of vaccine recipients missed days of work or school because of these mild vaccine-related symptoms."
Here is a nice graph demonstrating no more smallpox.
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