The current emergency due to the expansion of cases of monkeypox has put experts around the world on alert.
In the United States alone, 10,768 cases have been confirmed until this Thursday, and worldwide 27,000 patients have been registered in 88 countries. The World Health Organization (WHO) declared a global emergency for the disease.
Before 1980 a part of the world population received a smallpox vaccine. Most developed nations had made the smallpox vaccine optional since the second half of the 1970s, when the disease was considered eradicated.
With the outbreak of monkeypox, a zoonotic disease, some are wondering how protected those who received the smallpox vaccine are. Those who received it have a characteristic mark on the arm left by it.
Scientists consider that people who were born before 1980 and who have the smallpox vaccine would be protected up to 85% against the current outbreak of monkeypox, although in the absence of updated studies, they have not yet reached a definitive verdict.
The characteristic volcanic crater-shaped scar on the upper arm is the hallmark that the person received the smallpox vaccine.
However, in some countries the tuberculosis vaccine was also applied, which also left a mark.
To clear up the confusion of which is which, Canadian physician John Ross explains that the brands are different. In smallpox, the scar is sunken, while the tuberculosis vaccine left a raised or raised mark, noticeable to the touch.
Why did the smallpox vaccine leave marks?
The scar left by the vaccine is not a mark to identify vaccinated from those who are not, but was produced by the technique with which it was applied, explains the Salvadoran doctor and infectologist Jorge Panameño to the Voice of America.
The scar is due to the two-pronged bifurcated needle with which the serum was applied, very different from the hypodermic needles with which it is immunized today. This method was used until the late 1970s.
The health personnel trained to apply the vaccine had to submerge the two-pronged needle in the solution and there should be a drop of the substance on both ends, the skin was pricked about 15 times in a few seconds.
That incision generated a protuberance of blood that, when dried, left the singular mark and at the same time evidenced the effectiveness of the vaccine in the immunized person, explains the Panamanian doctor.
“At that time it was determined that the protection of this vaccine was for life,” he said.
“So far, no study has been published that indicates that after 40 years or more of having received a single dose, the same level of efficacy of 85% is obtained,” explains the doctor. “The hope is that yes, but studies have to be done, because the immune system also ages.”
What is the difference between the different types of smallpox?
The virus responsible for smallpox belongs to the orthopoxvirus group, of the poxviridae family, explains the United States Centers for Disease Control and Prevention (CDC).
This family of viruses is believed to have been present among various mammalian species for about 3,000 years. The devastations caused by pandemics over the centuries testify to this. In the first quarter of the 20th century alone, before a global vaccination campaign began, some 300 million people worldwide died from this virus. The average mortality was around 30% in some groups.
Among its relatives are the viruses that produce cowpox, horsepox, camelpox, buffalopox, rabbitpox, mousepox, monkeypox, and raccoonpox, among those known.
The presence of fluid-filled pustules that leave deep scars on survivors as they dry out and flake off are the most noticeable signs of smallpox, along with high fever and other complications in each clinical picture from the immune response, experts explain.
Scars found on Egyptian mummies some 3,000 years old indicate that the disease already existed in those immemorial times, but it is unknown exactly when it reached humans. Later descriptions of diseases in China hint that smallpox devastated part of today’s Asian power in ancient times.
Currently, the CDC indicates that a recurring symptom among patients who acquire smallpox is swollen lymph nodes, a sign different from that of smallpox. Also in different parts of the body, especially in the area of the genital organs, painful lesions have been discovered, “more than pustules”.
“The swelling of the lymph nodes can be generalized and affects many parts of the body” such as the neck and armpits, according to the CDC. Only laboratory tests can certify the presence of the virus, because the appearance of symptoms also varies .
The incubation periods of the virus also vary. The human smallpox manifested itself between seven and 19 days after infection. In monkeypox, it has been calculated that it would be around between five and 21 days, with the range of manifestation of the first symptoms being between seven and 14 days.
Scientific reports indicate that monkeypox, for which the WHO has decreed “maximum alert”, was reported in 1958 in an outbreak of primates under observation for research.
In humans, the first data indicate that the first detected case was recorded in 1970 in the Democratic Republic of the Congo. Outbreaks of the disease were considered endemic in parts of Africa until it began spreading around the world in May this year.
Where does the virus in the smallpox vaccine come from?
The review of historical documents indicates that the efficacy of the vaccine was considered a total success, being around 95%. Stopping the disease that caused up to 30 deaths for every 100 infected and disfigured the skin with deep scars for the rest of the survivors’ lives was considered an achievement of science.
For many years it was believed that the inert virus to immunize against human smallpox came from the variant that affects cattle, bovine smallpox, and hence the name of the puncture to inject the serum and the technique was called “vaccination”, from the Latin “vaccinus”, whose meaning is “of the cow”.
But new scientific research indicates that it could be a variant of the horsepox virus, although there is no certainty due to the lack of documents and due to the lack of interest in the disease for about 40 years, when its eradication began to be considered, which It became official in the late 1970s.
Until 1939 no one questioned that the vaccine for humans, “vaccine” came from bovine smallpox, explained to the press the virologist José Esparza, from the Robert Koch Institute, in Germany. “Then it was discovered that they were different.”
In the current outbreak, explains the Panamanian Dr., it has been decided throughout the world to use the two previously recognized vaccines that have the certifications and tests, ACAM2000 and JYNNEOS, according to CDC guidelines.
“The smallpox vaccine was held more as a strategic reserve, that has changed at this time,” he explained.
When in 1980 vaccination against smallpox ended worldwide by mandate of the WHO, it was not estimated how many people would have died from the disease in previous centuries. It has only been recorded that it was one of the deadliest infectious diseases in the history of mankind.
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