Know your pandemic

Book review of Covid-19: Separating Fact from Fiction

An alternative title for this book could have been “What you didn’t know about viruses, pandemics, and vaccines, and wanted to ask”.  In simple language, assuming no previous knowledge, the book does a breezy run through these broad topics.

It gives a sense of how viruses work, the current state of the art with reference to Covid-19, the art and science of vaccine-creation, drug-testing, and immunisation doctrines, the treatment of unknown diseases, how epidemiologists study disease and their influence on public policy. The end notes add rigour by listing key studies across these domains. As the author Anirban Mahapatra says, this is the first time millions who are feeling perfectly healthy have wondered if they were, in fact, infected by a potentially deadly disease. It is definitely the first time vaccines have been developed and unleashed on global populations at such a breakneck pace.

The Covid-19 pandemic had been predicted, down to almost every heart-breaking detail, by dozens of scientists. A group speculated in 2018 that “Disease X”, a new deadly coronavirus, would at some stage make the transition from animal to human. It happened only a year later! Until the early 2000s, coronaviruses were a research side-line. Few were known, and at worst, they caused mild colds in humans. Then SARS (Severe acute respiratory syndrome) arrived. That was followed by MERS (Middle East Respiratory Syndrome).

Both had high degrees of lethality. Both were zoonotic. They were present in animals and mutated and jumped to human beings, from bats via civet cats in the former instance, and from bats via camels in the latter. Other zoonotic diseases such as Ebola and Nipah also arrived in the early 21st century.

We still don’t know where SARS coronavirus 2 (SARS-CoV-2) originated. It may have originated in bats, and transited to pangolins before it mutated to target humans. Studying rates of mutations, researchers believe it may have taken decades mutating through natural selection, unless it was patched together in a lab, as conspiracy theorists suggest. 

What are viruses, and how do they replicate? Drug and vaccine researchers need to know this before they can craft effective counter measures. Luckily, genome sequencing techniques have progressed rapidly in the past decade. The genome was decoded within a few days. This helped quickly develop test procedures that work by detecting either the virus (or virus debris in the case of a recovered patient) and antibodies (which indicates exposure to the virus at some stage even if the person was asymptomatic).  RNA vaccine manufacturing techniques, which accelerate vaccine creation, have also improved. This is why dozens of labs could rapidly cook up potentially effective vaccines.

Covid-19: Separating Fact from Fiction

Author:  Anirban Mahapatra

Publisher: Penguin Viking

Pages: 249; Price: Rs 599

Trialling a new drug or vaccine is a complex process. Timelines can’t be crunched beyond a point. The concept of a double blind trial is that the doctor doesn’t know if a given drug, or vaccine has been administered (neither does the patient). After a while, the data is collated and infections, recoveries, and so on are studied. Researchers need to know the baseline recovery rate for patients who have not received treatment, and they need to know likely rates of infection before they can make sense of the results.

As the book explains, this is even more complicated with Covid-19. Some patients recover quickly or remain asymptomatic.  Even now, after millions of cases, we don’t have a clear idea why some have high resistance. Nor do we have a clear idea of fatality rates, or infection rates, for that matter.

Along with “flattening the curve”, “herd immunity” has entered the popular lexicon. What percentage of a given population needs to be immunised either through infection or vaccination before the disease ceases to be a serious threat? The higher the infection rates, the more the percentage of people who need to be immunised.

As the book explains, Covid-19 has both high and low infection rates. The majority of Covid-19 patients don’t infect many others. Some infect many. The virus spreads mostly via a few “super-spreaders”.

This complicates herd immunity calculations. Infection rates are represented as a ratio R0 (“R nought”) and averaged out. An R0 of 1 or less implies one infected individual will infect one (or less) persons, leading to the disease quickly easing off. In Covid-19, the “average” infection rate is low. But average is less meaningful since one super-spreader may infect dozens.

It is likely the disease will become endemic, rather than epidemic. It is also possible, even likely, given multiple mutations, new vaccines will have to be developed at frequent intervals. It is more or less guaranteed that more unknown coronaviruses, or other zoonotic diseases will arrive in the future. As a race, humanity needs to extrapolate from this experience to evolve public policy to handle the next crisis better.

Although this book was written as topical commentary on the pandemic, it deserves to be a keeper. It has many of the hallmarks of a popular science classic due to the breadth of coverage and the lucidity of the explanations. Read and squirrel away for reference when the next pandemic arrives.