Influenza vaccination amongst hospital health care workers in Beijing. 2010, Seale, Occup Med Lond

Only 13% of doctors and 21% of nurses vaccinated against influenza.
40% of health care workers believe that flu vaccine can cause flu. (Beijing, China)


Varicella outbreak in a highly-vaccinated school population in Beijing, China during the two-dose era. 2017, Suo, Vaccine

A chickenpox outbreak in a school where 98.6% were vaccinated, 63.2% of them were given in two doses. Among the unvaccinated, 14.3% were sick, 1.6% of those vaccinated with one dose, and 2% of those vaccinated with two doses.
The authors conclude that to prevent outbreaks, a higher coverage of vaccination with two doses is required.


The tetanus bacillus as an intestinal saprophyte in man. 1922, Tenbroeck, J Exp Med

The answer to the question, how natural immunity is produced was already given back in the 20s of last century. Tetanus bacteria were found in the intestines of 35% of the 78 men tested in Beijing. Tetanus was a very rare disease in China in early 20th century (not counting the neonatal tetanus).
Researchers found tetanus bacteria in the patients’ stool even after they spent three months in the hospital on a virtually sterile diet. This can lead to a conclusion that tetanus bacteria multiply in the intestines.