The following question was received. Due to a high interest on this to, we have decided to share our response with the public. Please find information provided below.

QUESTION:

I just read about a new wave expected to hit in May/June in Cape Town, perhaps someone could shed some light on something that we are curious about. How do they predict and calculate these waves of the pandemic hitting in advance?

RESPONSE:

There is a whole part of Medical Science called Epidemiology, which studies the spread of disease or its prevalence.

Definition: “The branch of medicine which deals with the incidence, distribution, and possible control of diseases and other factors relating to health”.

Epidemiologists are people who specialise in this today but it has roots going back to the Islamic Golden Age, when many of these sciences where formalized!  (Al Razhi aka Rhazes, Ibn-Sina aka Avecinna, etc)

Like many others, they are a profession that previously few noticed or cared about, but quietly did a very important but “unexciting” job. Epidemiology uses previous experience, statistical information as well as knowledge concerning how a disease works and differences in human behaviours, to project “what is likely to happen going forward”.

The “smarter” the people, and the more information we know about the disease… the more accurate our projections become. (In addition, SA has many globally recognized experts).

Early Projections

With COVID19 and during the first lock down/wave there was very little information about the disease, as it was completely new. Many things were educated assumptions or ideas. We were fortunate that our lockdown happened when it did as the extra few weeks and months meant there was more info when we did get our first wave.

After the June-Aug peak there was far better information around how COVID19 spreads among communities (human behaviour) and how the virus itself compares to other infectious organisms (the disease profile).

Why are scientists predicting a wave in May/June in South Africa?

There are many reasons and the experts’ use many more factors but the most obvious are time, disease and behaviour.

Time

Looking at the gap between the first wave and the second wave it took around four to five months from June – August to November – January. Assuming that we are able to control the virus and human behaviour will follow the same pattern we should expect another cycle in between four to six months (May/July).

The post-1st wave projections may not have accounted for the SA mutation of the virus, which seemed to have happened/taken hold in the Cape Region. This meant that the expected Jan-Mar wave happened earlier.

People

Looking at how people move in their community, and the country and the high probability of movements during the April holidays, the return to universities, work etc. It is reasonable to expect it could take about another four to six months from the previous peak in January to the next Wave.

Sooner or Later?

Many things can change this:

• Human Behaviour – If people do not behave the way that they are expected to and are more careful it could push out the wave until later or reduce its severity when it does happen BUT if people are not so careful, it may happen sooner!
• Mutation – if the virus mutates again it could be more virulent OR less virulent. (Make you more or less sick)
  This could mean the wave could come earlier or later, OR it is bigger or smaller a wave!
• Treatments – with the first wave and especially in places like Italy, the protocols for treatment were still being developed, and had limited knowledge of the disease.
• Subsequently, better treatment has meant that despite the peak, the effect was actually much better then we could have experienced if we had not locked down and delayed the spread.
• Important: The Vaccine effects will take a Long Time – even if we started a vaccination, program today and somehow rolled out to, e.g. A million people in the next 10 weeks (100,000 per week), It is unlikely that we would be able to prevent another wave.

However, there will be a huge benefit with any vaccinations (especially for those who are at highest risk) as it will reduce the likelihood of them spreading the disease and ensure that we have more people, especially Healthcare workers able to treat those who do get sick.

Why Cape Town? (It is not the mountain 🙂 )

That is where the first and second waves started. However, there is also data showing that Western Cape is more accurate in its COVID19 reporting than other provinces (e.g. MRC Excess Deaths Research). It may start elsewhere or simultaneously in other provinces. This is also why testing and isolation is important, even in mild/asymptomatic cases.

The Numbers Don’t Lie

Epidemiology is not very different from using science to predict changes in the economy, politics, growth rates, technology, weather etc. and is never an exact science… HOWEVER, the more variables you use, and the more accurate data becomes, the more likely the predictions are correct.

Can a New Wave be prevented?

The biggest unknown is HUMAN BEHAVIOUR!

Probably not “prevented” but if ALL of us respond better, do what the Scientific Experts, Specialists and Doctors advise and be more vigilant, we could Delay or Lessen the Peak. If we can delay it until we get enough people vaccinated, maybe we could (and I hope) even avoid a third wave!

Most importantly, our Safe Behaviours will SAVE more lives!

Regards

Mr M. Kharwa
Pharmacist