Pakistan crossed another grim milestone on Monday as the national COVID-19 death toll crossed the 12,000-mark amid calls for procuring vaccines for the general public.

Current scientific understanding is that only a vaccine will put an end to this pandemic, but how we get there remains to be seen. It seems safe to say, however, that some day, somehow, it will end. After all, other viral pandemics have. Take, for example, the flu pandemic of 1918-1919.

In the case of the 1918 pandemic, the world at first believed that the spread had been stopped by the spring of 1919, but it spiked again in early 1920. As with other flu strains, this flu may have become more active in the winter months because people were spending more time indoors in closer proximity to one another, and because artificial heat and fires dry out skin, and the cracks in the skin in the nose and mouth provide “great entry points for the virus,”

What do we know about the end of the Spanish flu 100 years ago?

As a child back in Europe, I’ve learned about the Spanish flue from two sides: In gymnasium where our history professor had an addiction to the Spanish flu and the Holocaust.

My second source of reference was my great grandfather, who was a very young child when the Spanish flu hit Europe, including Austria, where he grew up. He used to tell me long stories about it, when I was a little girl.

His recollection of the actually pandemic wasn’t that strong. He remembered, however, the aftermath of it, as it lasted many years for the economy and individuals alike to recover. Nevertheless, I have heard and learned enough to share it with you below.

According to unconfirmed estimates, the largest influenza pandemic of the 20th century (from 1918 to 1920) killed around 100 million people. Some say it was “only” 50 million. Newer researches, however, estimate at least double the amount, as the disease came in three waves and not all deaths had most likely been documented. This mega-pandemic went down in world history as the Spanish flu.

According to today's knowledge, however, it did not begin in the sunny south of Europe, but on the Army base Fort Riley in Kansas. The cook Albert Gitchell is often named as one of the first patients. Within a few days, more than 500 men fell ill in this military camp.

How did people get infected?

Back then, people were just as infected as they are with seasonal flu today. There are basically three transmission routes:

One is the infection via the droplet infection, even over several meters.

The other is contact infections. For example, when I cough into my hand and shake hands with someone else, who in turn grabs his mouth or nose.

And the third possibility is actually smear infection, because the influenza virus has the property that it can survive outside the human body for a certain time, depending on the temperature. It could theoretically be that someone grabs an elevator button, the next one grabs the same place and becomes infected through it.

Why was the Spanish flu such a killer?

One is the pathogenicity in the pathogen itself, i.e. the basic ability of infectious organisms or toxins to make a certain organism sick. The Spanish flu was a variant of the H1N1 type that was very disease-causing to humans. Such pathogens arise through certain mechanisms. If a pathogen is completely new to the human organism, i.e. a subtype, it can attack humans particularly quickly.

The other are properties in the host that is, so to speak, surprised by a new pathogen, and the third is the circumstances. It was a war back then, and the pathogen initially spread in a military camp. Such group facilities are the ideal prerequisite for dissemination. Then it was brought by the troops to Europe, including France and Spain.

Even today, increased mobility plays a major role in the spread of pathogens. These troop movements made it possible for the pathogen to spread to other populations. And such crowds, as you can find today in large cities, favor the spread of a pathogen due to the high contact rate.

What treatment methods were there?

Treatment methods were still limited 100 years ago. At that time there were no vaccines against influenza, there was no antiviral drug (term used here for: drug that inhibits virus replication), and there were also no antibiotics as we have them today.

What was done at that time was purely symptomatic treatment. This still plays a role today.

At that time, aspirin was used, which also has anti-inflammatory and pain-reducing effects and has a beneficial effect on the symptomatic course of the disease. Other methods included normal bed rest, inhalation, or nasal showers, on a symptomatic basis. People have also tried to take drugs from other diseases.

My great grandfather remembers that he was looking out of the window of their home, where he witnessed people carrying others that had fallen ill outdoors into the glaring sunlight. It’s said that many actually recovered from the Spanish flue because they absorbed more heat (natural sunlight) and/or more vitamin D. That’s why doctors and scientists are suggesting vitamin D as a defense against Covid-19, as well.

One has been given quinine, for example, which successfully helped against malaria, but also morphine and heroin against the pain. And at that time, for reasons incomprehensible to me, they also injected mercury, because they believed that it would be helpful. So they partly used martial aids. The pathogen causing the catastrophic Spanish flu is still in circulation today, according to a new study.

Do we need to worry about a subtype of the H1N1?

To be precise, a subtype of the H1N1 virus also appeared in the 2009/2010 pandemic flu, i.e. swine flu. This is actually the same ‘tribe’. And through mutation or the transfer of entire gene segments, certain subtypes always arise that are either relatively new to humans or completely new.

Today the WHO (World Health Organization) reckons that a certain part of the population is also infected with H1N1. It is nowhere near as pathogenic, however, as the causative agent of the Spanish flu at the time. It's a different subtype. The H1N1 strain is, of course, still available in different variants.

How big is the risk that we will get another pandemic like this?

As we can see now with the Coronavirus, a pandemic of any type can never be completely ruled out. It's a game of chance. And such pandemic strains as occur in the Spanish flu virus always arise from the exchange of genetic information between different virus subtypes.

So two strains of influenza, namely a bird strain and a human pathogenic strain, exchange genetic segments. This in turn develops properties that are completely new to the human immune system, antigenic structures, and, thus, can cause a new epi/pandemic.

Possible antibodies for eventual future outbreaks

Even 90 years after the outbreak of the devastating Spanish flu, antibodies against the virus can be found in the blood of survivors, report doctors from Vanderbilt University Nashville in the US state of Tennessee. I read this in the online edition of the journal "Nature".

The researchers found 32 people who had experienced the flu pandemic themselves. The analyzers found antibodies against the virus from 1918 in their blood. They even found so-called memory B cells in the blood that produce these antibodies. After the scientists injected these antibodies into mice, the animals were protected from a fatal infection with the flu virus.

Should this flu ever occur with a similar virus type, such antibodies could also be used therapeutically.