As you have seen in my previous blog post, smallpox which was once a pandemic has demonstrated complete eradication. Let’s look at its journey of success from being a pandemic to eradication.
What is smallpox?
Smallpox is an acute contiguous disease caused by two strains of the variola virus: variola major and variola minor belonging to the family of orthopoxvirus.
It is similar to COVID-19, especially the delta and omicron variants in terms of its mode and rate of transmission. It transmits primarily through close contact in indoor spaces.
Symptoms of smallpox:
Symptoms include the presence of small red spots on the tongue or mouth, which later change into sores that break open to release the pus inside them and spread the infection into the mouth and throat through sores known as pustules.
The patient experiences fever during this infection. In addition, the patient may exhibit flu-like symptoms like muscle aches, headache, fatigue, back pain, and vomiting.
Different stages of the symptoms: early rash to scabs
Early rash- it starts in the tongue and spreads to the insides of the mouth and throat. Red spots soon become sores which break open to release pus
Spreading rash- the rashes spread to the face, arms, legs, back, and torso and eventually spread all over the body including palms and feet
Bumps with pus inside- initially the bumps may have a dent in the middle and over two weeks start to fill with pus
Pustular rash and scabs- bumps become round lumps called pustules and crusty scabs form over the pustules over the next 10 days
Resolving of scabs- after about a week, the scabs will fall off leaving scars
The severe scarring was a complication of smallpox. Other complications include blindness, encephalitis, inflammation in the lungs, bacterial infections, and arthritis
The rate of survival is high, but, there are a few types of smallpox that are almost always deadly. Pregnant women and immunocompromised people face a high risk of infection.
Treatment:
There was no known treatment for the disease at that time. However, effective vaccination helped prevent the patient from developing an infection if given within 4 days of exposure to the virus. This strategy worked well and helped towards the eradication of smallpox. In addition, isolating the patient (quarantine) can help prevent the spread of infection.
Two vaccines were available for the smallpox infection. They were:
ACAM2000 which consists of a live virus like smallpox but is less harmful. Due to its serious side effects like infection in the heart and brain, this vaccine is not recommended given to everyone.
Jynneos, the second vaccine consisted of a very weakened strain of the virus and was a lot safer than ACAM2000. Immunocompromised patients and patients with skin disorders can take this medicine
Why was it a pandemic?
Smallpox devastated America in the early 1500s after their contact with Europe. Its death toll was hard to measure, but, just the 20th century alone estimated around 300-500 million people. It was one of the most devastating pandemics and is known to have caused millions of deaths around the world before its eradication in the year 1980. It existed for almost 3000 years before its eradication
Smallpox and its eradication
Being the biggest killer in history with over 30% mortality rate, it was more contagious than COVID-19. But, how they eradicated it is a fascinating and inspiring journey that we may use for the eradication of other pandemics. Let’s see how it was completely eradicated on May 8th, 1980.
Dr. Edward Jenner-1796
It started with the pioneering work of Dr. Edward Jenner in 1796. He noticed and demonstrated that patients who had contracted cowpox, a milder version of smallpox developed immunity against the virus. This began the immunization efforts across Europe. By 1813, the US Congress ensured the availability of smallpox vaccines throughout the US. Very soon, other countries like Bavaria and Denmark followed and rigorous efforts were taken to immunize all patients contracted with smallpox. By the 1900s most countries in the US and Europe had eradicated the disease. But, smallpox did ravage other parts of the globe and nearly 10-15 million people caught the infection annually.
World Health Organization- 1950
However, it was not until the 1950s with the establishment of the World Health Organisation (WHO) in 1948. Despite the skepticism from several people, advancements in the field of medicine through needle technology and overseas travel made easy ensured the worldwide distribution and injection of the vaccine.
What made smallpox different from COVID-19
One important factor that helped drive the eradication of smallpox virus was its absence in animal reservoirs. This is what makes smallpox different from COVID-19. Due to this, once it was destroyed in humans, it was gone forever. And also, only one dose of vaccine was required for the rest of the person’s life giving lifetime immunity to the patients against the virus.
A second advantage of smallpox infection when compared to COVID-19 was that it did not have asymptomatic transmission. Exploiting this, a unique strategy on ring vaccination was developed wherein if one patient comes in with an infection, everyone who came in contact with that person will be vaccinated. This ensured a large population of people were vaccinated in a short time. This strategy was a pivotal change in the eradication of smallpox.
Outbreaks in developing countries like Somalia and Bangladesh were still happening, but with contact tracing and ring vaccination, the numbers slowly started to decline. Eventually, on May 8th, 1980, the World Health Assembly officially declared victory against the smallpox virus.
There were important factors that helped in the eradication of smallpox. They were:
- Only humans got infected with the virus: the infection did not spread to animals
- Easy identification: unlike COVID-19, there were no asymptomatic patients. The characteristic rash on the skin was easily identified
- Relatively slow rate of transmission: it wasn’t contagious until an infected person was too sick. It usually only spreads to members in the same house
- Ring vaccination: as mentioned before, this was a turning point and led us toward the eradication of smallpox
- Survivors had immunity: since smallpox has been around for several years, very few people needed to be vaccinated as the survivors of smallpox already had immunity
Can this strategy be used for the eradication of other viral diseases?
Despite our proudest moment and humanity’s triumph victory against the smallpox virus, that success was never replicated for any other virus. Although a close call was observed with the polio vaccine (Wild polio has been eradicated in Africa), we have let other diseases like HIV or COVID-19 take over as a pandemic.
The main challenges in reciprocating the eradication of small pox to other viral diseases are its transmission from animals and asymptomatic infections. This makes it difficult to control the spread of infection. But, these are things that we cannot control. There are a few things that we can control.
About smallpox, its eradication scheme was well funded by the government. Healthcare workers risked their lives to visit remote villages and they could not have done it without strong funding. The commitments of governments of rich countries to not leave behind the funding needs of poor countries played a crucial role in the success of smallpox eradication. Yet another important aspect of this story of eradication is that the remaining vials of vaccine were destroyed to prevent an accident or a malicious act of releasing the virus into the environment again. Only two laboratories have stocks of the virus- one in the US and one in Russia. They have it only for research purposes.
Even though COVID-19 cannot be eradicated, we must note that it could have been much worse. The devastation of COVID-19 has brought to light the role of public health experts and epidemiologists who play a crucial role in disease surveillance programs.
Do you think we can take inspiration from smallpox eradication and use a similar strategy for the eradication of COVID- 19? I would love to hear from you.
If smallpox could effectively be prevented with cowpox since it’s the same family, why can’t we all just take the weak forms of a virus from every family and prevent all the viruses in the future?
Interesting thought. There is no doubt that cowpox could be used to eradicate smallpox as it was a milder version of smallpox. However, that was not the only factor. There were other reasons for its successful eradication, like the ring vaccination system and the absence of smallpox in animals. But, we currently are not aware of less infectious variants of other viruses. Taking an example of COVID-19, its fast paced mutation rates makes it difficult for us to cope up. Every variant is stronger than its previous counterpart with regard to its rate of transmission and mortality.Check out my post on COVID-19 to know more.
What if we assume that there are only so many virus families and we start taking a vaccine of every weak virus we can find, wouldn’t we be able to eliminate even the ones we don’t know of yet and possibly weaken the effect of some of the known ones or even completely destroy them.
A lot of work has been going on with regard to eradication of viral diseases. Despite vaccine research for viral diseases, smallpox remains the only viral disease in humans to be completely eradicated. There are other viral diseases like polio, tetanus, rubella, measles etc. which we have almost forgotten thanks to their vaccination efforts. These diseases have not been completely eradicated but have become manageable due to their vaccination routines. The strategy of using a milder version of the virus as a vaccine did not work here as they never found a milder version.
Hope this helps!
A write up of the latest breakthroughs and ongoing research in this regard would be great. Thanks for taking the time to answer!
Sure. You can look forward for a post on this.
Thanks for sharing!