Smallpox the First: a human triumph!


Lady Mary Wortley Montague (1689–1762)

Source: Reidel 2005, Photo courtesy of the National Library of Medicine.

Smallpox the First

Did you hear the good news? Smallpox is dead!  The smallpox virus was murderous.  It killed more people than war.  In the 20th century alone, smallpox killed between 300 million (300,000,000 or 3*10^8) and half a billion (500,000,000 or 5*10^8) people.  The first disease conquered by humans: How did we vanquish this angel of death?

Continue reading


What’s a vaccine to you?


A vaccine against ignorance?  “Humanity certainly needs to be immunized with a vaccine for ignorance, and we propose that that vaccine is education. But education would have to be coupled to restrictions on people, agencies, and corporations determined to follow the profit motive, and in so doing, undermine the intelligence of the populace.”

Vaccines have been so good at preventing disease, that the above article uses ‘vaccine’ metaphorically to describe prevention of ignorance.  And has been used to describe other preventive interventions: what would you like a vaccine for?  Something to stop what you don’t want.  I would like a vaccine to be more kind and less mean; to love.  Sadly, we have not yet discovered that.  But education and changing the economic system could help.

The picture above uses shapes, sizes, and colours to show different bugs; and the hand as defence that stops them. Vaccines stop harmful bugs by preparing our defences. A vaccine does not protect against bugs in general, only the specific bug that it targets. It does this by ‘looking like’ the bug to our immune system.

Continue reading

Love & Logic

Time for a philosophical break on this journey.  I started Vaccine Logic to see if I could teach vaccines and mathematical tools including logic. But as Aristotle said, “Educating the mind without educating the heart is no education at all.”  And I realised that learning about vaccines and immunisation is also about emotion.  We are emotional and not rational creatures, by instinct.

But we can and do over-ride instinct routinely.  Isn’t that what it means to be civilised: to do what is moral rather than what instinct or pleasure dictates to meet self-interest?  To over-ride our natural prejudices with deliberate logic.  We can recognise our biases and address them if we choose, but it is hard work!  Discipline and practice.


Love requires empathy, a feeling for others. “When parents use empathy and don’t react negatively to a child, they help the child stay in the upstairs part of the brain (more rational part) and not the downstairs (emotional).”

It is wrong to think of love as a purely human attribute. Love emerges in the animal kingdom with mammals and birds, who care for their young.  Fish spawn and move on. Reptiles will carefully hide their eggs then leave them.  Love starts with the care of the mother for the child; and there are many kinds of love.  An army unit works as well as its members love each and will protect each other.  At heart is the care for the other, and willingness to sacrifice for them.


The primate love instinct that we inherited has gone metaphysical: a love not just of other people, but also of ideas.  Continue reading


The germ theory of disease

Your immune system protects you from bugs: harmful micro-organisms. These are tiny living organisms that can infect and sicken us. There are many types, including:  viruses, bacteria, fungi, protozoa.  It might surprise you to know that it is a very modern idea that germs – another word for bugs – cause disease.  The germ theory has only been widely accepted since the second half of the 19th century, and is still not accepted by some.

Please allow me an arithmetic deviation. When was the 19th century?  Our calendar starts with Jesus.  A century is 100 years, so we describe the first 100 years after His birth as the first century.  So the 19th century are the years from 1800 to 1899, or the 1800s.  In 2016, we are living in the 21st century: science fiction for me,  growing up in mid-20th century.

Wikipedia tells me that germ theory was originally proposed by Girolamo Fracastoro in the year 1546. (I wonder if there has been adequate credit given to earlier Chinese or Greek thinking.  Most ideas can be found in these classical sources,   confirming the biblical verse that ‘there is nothing new under the sun’. ) The microscope was only developed in the 16th century, and it was not till 1676 that  Antonie van Leeuwenhoek discovered micro-organisms.  He had developed a microscope with up to 300 times magnification and  discovered red blood cells and spermatozoa (or sperm, if you remember where you come from).

The role of micro-organisms, or bugs, in causing disease remained controversial until medical science advanced. As these bugs are too small to be seen, they were not discovered until we had microscopes.  Viruses are much smaller than bacteria, and cannot be seen with a light microscope.  An electron microscope  allows us to see viruses, but we can also see the effect of viruses on the cells they infect on a lab dish.  The first virus was only isolated in 1898, influenza virus in 1933.

The cartoon above shows the key features of the influenza virus: the two proteins that it uses to get into and out of the cell it infects and takes over, preparing billions of copies of itself in the infected cells.  Below, you can see these two proteins as well as the 8 strands of its genetic code, each coding for the proteins that make up the virus.  Influenza is an RNA virus, meaning its code is made of RiboNucleic Acid.  In contrast, bacteria and humans use DNA, or DeoxyRiboNucleic Acid, as our genetic code, in each of our cells.



The influenza virus 

Source:  where you can see other types of virus.

Our understanding of the immune system is even more recent than of bugs.  Many different types of viruses cause disease; and even more so for bacteria. For most viruses, including influenza the symptoms we get are not from the infection itself, but from the body’s attempt to remove an invader that has breached the initial defence barriers of skin, gut, or vagina.  This is why many viruses will cause an influenza-like illness.

Other viruses, like measles, polio, or Ebola each have distinctive patterns of illness, that still is the reflection of the battle between the virus and the specific tissues that that virus has a propensity to attack. In addition to an acute infection, some vaccines can be carried for a long time to be reactivated as shingles or cancer. hepatitis B and human papilloma virus cause cancer of the liver and cervical cancer, respectively.

The immune system does not only protect us from these infections, but we can teach the immune system so that it can defeat an infection before it sickens us.  But to understand the immune system, we first need to understand cells….





Diversion on dates:

So, was Jesus born in Year zero or one? Probably neither, but in 4BC – which means four years before Christ is born, so how can that be?  The problem was this new calendar, called Annus Domini (AD) , was not established till some hundreds of years later.    The issue of whether to choose zero or one as the starting point is a computer coding question too.  Are you 0-day or 1-day old on the day your are born?  The zero itself was not born till seventh century India, around 650 AD (7th century), though did not reach Europe till the 12th century I hope by now you will recognise is the seventh century after His birth.  And that in 2016, we are living in the 21st century.  Can you believe it?

Vaccines and numbers

The story of vaccines starts with a new child (is it you?) arriving into our strange quantum world; where particles come into and out of existence, by charm, spin or whim.

Each of the seven billion, or so, human beings alive at this space-time have this shared story.  It starts, when one (1) sperm joins one (1) egg & become (1) you. Did I just prove that 1+1 = 1?

But, 1+1=2.   Can both be true?  Yes, 1+1=2, has to result if the 1 refers to the same thing.  If not, it can also be 1+1= 3:  (1) Mum + (1) Dad  become a family of three, when you are born. And more as the family grows.

It all depends on both numbers counting the same thing.  In the case of sperm and egg, this is a special relation where both become a new thing: you!  There is also matter and anti-matter that together become nothing (1+1=0). (Strangely, this means that from nothing we can get something in the reverse process that is constantly happening in the sub-atomic world of this strange  quantum physics…


Why all this? To torture numbers?  The number is only valid, if the logic is correct.   If the logic is incorrect, the number is either meaningless, or can even mean the opposite.  It helps to understand numbers, if you want to understand vaccines.  Numbers can be used to confuse as well as illuminate.

In Propositional Logic, a statement of fact, or proposition, has Truth Value of  ‘1’ if ‘True’, and ‘0’ if ‘False’ . In Fuzzy Logic, numbers can also between 0 and 1, as this can better describe the world than the sharp categories that our minds make up.

So, what does number ‘1’ mean?  It defines the unit, the thing.  It is also the space between numbers – a unique role.  I hope you know all your numbers, but if you keep adding 1 you will never get to infinity, just a bigger number.  If you like big numbers let be introduce you to the Googol (10^100 or 1 with 100 zeroes after it) and Googolplex (10^Googol). The Googol alone is so unimaginably large that it exceeds the dimension of the known universe, nearly whatever units one uses.

So, you are 1 in 7 billion and more living breathing human beings on planet Earth-today.  One billion is a huge number:  (10^9 1,000,000,000).  It is biologically unprecedented for a single species to cover the entire planet. All of us from a small family that arose in Africa about 200,000 years ago, and survived climate change to emerge smarter.  Prof. Harari suggests that the Cognitive Revolution, about 70,000 years ago, led us to outcompete the other human species: at least half a dozen (which is 12; i.e., 6) that existed around that time.  From Africa, our ancestors left  about 50,000 years to progressively cover the planet, making countless species extinct as we rose to the top of the food chain through the organising capacity of language.

These are some numbers that can give you a perspective of your life, which is so short compared to these numbers, even smaller compared to the estimated age of Earth at 4.5 billion years.  The Bible gives us  ‘three score and ten’ or 70 years  (so how much is a ‘score’ – an old English measure?)  But increasing numbers of people are living over 80 or even 100 years; many in good health.  How long have you been here for?  And how long would you like to stay?  I often wonder if we go back to the place we came from, or this life is some small part of something that we cannot even comprehend.

Now, back to the start of your story.  A child is conceived (from the sperm and egg), grows in its mother’s womb for about 38 weeks and is then born on this planet.  The womb nourishes and protects you as that first cell divides and divides to become the trillions (10^12 or 1 with 12 zeroes).  Once born into the world, you are now exposed to the  risk of  bugs: microbial infections: bacteria, viruses and other parasites. You are born with natural defences against these, and also an immune system  that can be ‘trained’ to protect against specific bugs.

This is what vaccines do.  But first we must understand a bit more about bugs, and the germ theory of disease.