When Francisco Javier de Balmis set off from Spain in 1803 to vaccinate the people in Spain’s colonies against smallpox he had no means of keeping the vaccine fresh, so he used children as his refrigerators.
An exhibition of documents relating to Balmis’s voyage has opened at the Archivo General de Indias in Seville and will be on display until 15 September.
From the documents, we now know for the first time the names and ages of the children who made what was perhaps the first international humanitarian mission possible.
Manuel Álvarez, who curated the exhibition, described it as “a homage to all the health workers who have struggled against Covid-19”.
Smallpox was killing millions in 18th century Europe but in 1796 the English physician Edward Jenner discovered that a bovine version of the disease worked as a vaccine.
Balmis, who was a military and court doctor, persuaded Spain’s King Carlos IV, whose daughter had died of smallpox, to fund the royal philanthropic vaccine expedition to Spain’s colonies.
The objective, visionary in its day, was not only to vaccinate the population but to set up vaccination centres in order to control any future outbreaks of the disease.
The expedition set off from A Coruña in north-west Spain with 22 orphans on board. The nine-year-old son of Isabel Zendal, who ran the local orphanage, was among them. Zendal served as nurse and carer on the trip.
The vaccine survived for only 12 days in vitro so Balmis’s technique was to infect two children every 10 days and then take the serum from their pustules to infect two more children, and so on until they arrived at their destination with fresh serum with which to vaccinate people.
The children got sick but didn’t die and, although it seems barbaric, at the time it was considered quite normal. Jenner himself first tested his vaccine on an eight-year-old boy.
The original 22 children stayed in Mexico, where Balmis recruited a further 26 for the trip from Acapulco to the Philippines. The documents show that the children, all Mexican boys aged from four to 14, were handed over by their parents in exchange for payment. Some are described as “Spanish” and others as mestizos (mixed blood).
Three are listed as of unknown parentage and in the case of five others only their mother’s name appears in the documentation.
By the end of the campaign, about 300,000 people in the Canaries, Peru, Ecuador, Colombia, Venezuela, Mexico, the Philippines and China had received the vaccine for free.
“The strategy adopted by Balmis was a cheap, ingenious and pioneering solution to ensure that the vaccine arrived in the Americas in good condition,” said Alberto García-Basteiro, an epidemiologist and associate professor at the University of Barcelona.
“It’s likely that nowadays the strategy of using children to transport the vaccine would be criticised on ethical grounds, but the impact and benefits of the expedition cannot be denied.”
The Madrid hospital named after Isabel Zendal has played a key role during the Covid-19 pandemic. In 2000, when the Madrid government dispatched 2,500 soldiers to disinfect the region’s care homes, they dubbed it Operation Balmis.