History of the Smallpox vaccine

Category: News - Author: Dott.ssa Chiara Dall'Asta

Smallpox is a contagious disease of viral origin that is fatal in 30% of cases. The World Health Organisation declared the disease officially eradicated in 1980.

Because it is a viral disease, treatment with antibiotics is not effective, nor is there any specific treatment: the only way to prevent it is vaccination.

Due to the eradication of the disease, compulsory vaccination was suspended from the 1970s and 1980s in all countries. In Italy, vaccination was suspended in 1977 and definitively repealed in 1981.

Variola major and Variola minor

The most common is that caused by the Variola major virus, which manifests itself with high fevers and the appearance of ulcerating pustules all over the body. There are four such types of smallpox:

Ordinary form (more than 90% of cases);
Modified form, the symptoms are mild and it sometimes develops on previously vaccinated persons;
Flat form (also called malignant);
Haemorrhagic form, rare but very serious.

Smallpox caused by the Variola minor virus is less dangerous, with a mortality rate of less than 1%.

Manifestation and course

The incubation period of the disease, during which no symptoms occur, lasts from 7 to 17 days. Infection rarely occurs during this period, but starts when the first symptoms appear (fever, malaise, migraine, muscle pain and sometimes vomiting). This phase can last from 2 to 4 days and is characterised by hyperthermia, even acute at times. Subsequently, a very characteristic rash of small red spots appears, and this is the period when sufferers are most contagious. The appearance of spots can last for about 4 days and starts on the tongue and mouth. When the mouth spots become infected and turn to ulcers, new rashes affect the whole skin, from the face to the arms, legs and then the hands and feet. Usually the whole body is covered with spots within 24 hours. When the rash appears, the fever drops and the patient begins to feel better. Within 3 days, however, the spots turn into purulent blisters. At the same time, the temperature rises again and remains high until the pustules heal, becoming scabs that begin to flake and peel off.

Within 3 to 4 weeks after the onset of symptoms, most of the pustules have dried out and begin to detach from the skin, leaving a deep scar on the skin, known as pockmarking. The infection phase ends when all the scabs have fallen off.

Other smallpox and scientific discovery

In addition to human smallpox virus, there is also Cowpox virus, Monkeypox virus and Vaccinia virus. It was precisely the latter that was first used by the English country doctor Edward Jenner in 1796 to formulate the first proper smallpox vaccine. In 1753, 20,000 people died of smallpox in Paris; in 1768, 60,000 died in Naples within a few weeks; and every year, 40,000 people died of the Variola virus in England. Jenner found that milkmaids, who frequently contracted Cowpox, were unlikely to be affected by the human version. To prove his theory, Jenner vaccinated an 8-year-old boy (legend has it that he was his own son) with serum from cowpox pustules and then infected him with human smallpox, thus testing his immunity to it.

This represents the first documented case of active prevention of a disease, although other attempts at immunisation had already been made.

In the late 17th century, Lady Montagu, the wife of the English ambassador to Constantinople, had promoted the practice of smallpox inoculation in England, following a custom already widespread in the East. The same practice had also been introduced by Greek doctors in Italy and supported by Pope Benedict XIV who tried to spread it in the Papal States. Smallpox inoculation consisted of injecting a little pus from a recovering sick person into a healthy one, thus causing smallpox. However, this practice was often lethal. Jenner's discovery solved the problem, although it was opposed by ecclesiastical and conservative circles because it was considered an insult to the creator, given the animal and human combination. With the prevalence of libertarian ideas in the years following the French Revolution, vaccination became general practice.

Luigi Sacco and the spread of vaccination in Italy

In Italy, it was Luigi Sacco (1769-1836) who spread the Jennerian vaccination. A doctor in the Cisalpine Republic, he was born in Varese, graduated from Pavia and was head physician at the General Hospital in Milan. At the end of 1799 he vaccinated himself and then five children with pus collected from two cows suffering from cowpox. After some time, he verified his own immunity and that of those vaccinated with the human smallpox graft.

In 1806, Sacco reported that he had personally vaccinated or inoculated more than 130,000 people in the Mincio, Adige, Lower Po and Panaro Departments alone. In short, the number of vaccinated people in the Kingdom of Italy reached 1.5 million, drastically reducing smallpox mortality. The vaccine soon spread to the Kingdom of the Two Sicilies. After the unification of Italy, smallpox vaccination was made compulsory for all newborns from 1888.