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Maria Isabel Wittenhall (sometimes written as Witenhall or Wettenhall) was born in Avintes, in the municipality of Vila Nova de Gaia in November 1749 to English parents. The wine company, Curtis and Wettenhall, had been in existence since 1726 and her father, Townsend Wettenhall, was a partner in that company. He married Anna Carmer, a widow, in 1739. In May 1767, at the age of 17, Maria married Pedro van Zeller (1746-1802), a Porto resident who came from a Dutch Catholic family.


She became notable for promoting the use of smallpox vaccination at the beginning of the 19th century, particularly in the Porto area. For many centuries the disease had been treated by inoculation, which involved the deliberate introduction of material from smallpox pustules into the skin. This induced immunity but generally also produced a mild form of the infection and sometimes worse. The work of Edward Jenner in 1796 and others showed that cowpox delivered by vaccination could protect against smallpox. Jenner had noticed that people who dealt with cattle had resistance to smallpox. In reality, these people had been infected, but with a less potent strain of the virus – cowpox – which only affected bovines, and this gave them protection against the human strain. Jenner had the idea to isolate the pus or lymphatic fluid of the cattle and vaccinate humans. The word “vaccine” comes from the Latin for cow.


Smallpox vaccination was first introduced into Portugal in 1799. Wittenhall Van Zeller started vaccinating in 1805 on her family farm in Avintes and also at her home in Porto. At this time there was considerable suspicion on the part of the Church and the medical profession about the vaccine and she was once arrested for being a curandeira (quack or witch doctor). She appealed to the Royal Academy of Sciences for support and the Academy both successfully defended her and presented her with a gold medal in 1808. According to records, she administered 13,408 successful vaccinations between 1805 and 1819, or 18% of the total number given in Portugal during that period.


See also an article on Maria Isabel Wittenhall from our 2004 Annual Report