During the war, there was a severe shortage of anti-Diphtheria serum. With ingenuity, Prof Monteiro injected filtered toxin from the bacterial cultures into the jugular veins of some goats and bled them 3 weeks later to obtain the serum which he froze and used successfully to combat the epidemic that was spreading throughout Syonan-to (as Singapore was known during the Japanese Occupation).
Soon after WWII, common infectious diseases like Diphtheria took a heavy toll on lives of the children of Singapore. Prof Monteiro had fully expected that the scheme of inoculating pre-school and school children with anti-Diphtheria toxoid by the Singapore Municipality Health Department would work. However, the scheme was only a voluntary one, it did not achieve its desired effects.
Prof Monteiro insisted on making anti-Diphtheria inoculation compulsory with the force of the law in a joint meeting with the Public Health officials of both Singapore and the Federation of Malaya.
Prof Monteiro succeeded in making anti-Diphtheria inoculation a legal requirement in Singapore.
Another major pioneering medical achievement was his decision to use the untested oral Sabin vaccine on a massive scale to combat the acute anterior poliomyelitis outbreak in Singapore.
A quarter million children were immunised and the epidemic was brought to an end.
