‘This is the way the world ends, not with a bang, but with a whimper’ – the closing lines of TS Eliot’s poem, the Hollow Men, implies that the proverbial end that we tend to seek is often nothing more than a faint signal or the progressive fading away – so subtle you hardly notice it.

This is likely how the pandemic will end. First there will be a slow decrease in the news cycle, then any remaining restrictions will be quietly lifted, and soon life will resume back to normal. After a few months, people will look back and – with a hunch – assume that all is over with COVID-19. The pandemic ending, not with a bang, but with a whimper, a silent shift of attention away from the pandemic and the mortality numbers, and towards normal life as we knew it.

Sure we will have annual COVID-19 vaccines, and those that remain high risk will be managed more carefully as is appropriate for every annual flu season – but the pandemic as we see it, as it has entered our ethos – will slowly fade away.

When this will happen is less certain than how this will happen. And for many, that is the ultimate question: when will the pandemic be over?

Well, it will never be over, as the virus will forever remain in the virosphere that encircles the earth. But the real question is when will it be functionally over? – when can life resume back to normal?

All signs point to the second half of 2021 as the time when we can return to normal – we hope. But hope is not a strategy, and to be sure that the second half of 2021 is when life will effectively return to what it was, we need a few things to happen over the course of the next few months.

The first and most obvious being case fatality rates cannot rise beyond what the projections are stating. While the Institute for Health Metrics and Evaluation (IHME) has had more than its fair share of mistakes, it remains the gold standard for COVID-19 projections. And the CDC projection that aggregate all the various projections weighs the IHME projection the most heavily.

And all these projections show an increase in the number of cases and the overall mortality. But the rise in cases is far greater than the rise in mortality. An essential disparity we need to continue for the pandemic to inch closer to the end.

Even in Europe, the resurgence of cases has not translated to an increase in mortality. And in the United States, while the distribution of new cases has shifted across different parts of the country, and across different demographics, the detection rate and mortality rates have quietly shifted to be closer to the fatality rates of traditional influenza viruses. Which is still deadly no doubt, but not nearly at the eye-opening levels we saw early in 2020.

In fact, when seen over the course of the entire pandemic, the number of COVID-19 cases were like an average flu season, but the heightened mortality differentiated COVID-19 far beyond traditional flu seasons.

Now that mortality has decreased and is potentially approaching a steady state, the biggest factor predicting overall mortality is hospitalization. Or simply, if you get COVID-19, your mortality is like the traditional flu, unless you need to be hospitalized, in which case your mortality remains higher.

Which is why infection likelihood has remained low and case fatality rates have converged to an all-time low of 2%. People are smarter about avoiding high risk situations and contact with high risk individuals.

Meaning we are getting smarter about every day interactions.

Whenever we are introduced to new diseases there is a unique, morbid dance of sorts. People interact with the disease, some escape unscathed, and some are affected – until the disease and the population reach a steady state. This pattern has held true when the Native Americans were exposed to the European settlers, and indeed anytime new populations have interacted in the past. There is an initial acclimation period, and then the diseases and the populations achieve a steady state.

We seem to be approaching that. And it is an important marker to follow as COVID-19 spreads across different demographics and geographies – despite the change in populations affected. If the case fatality rates remain steady, then the population as a whole has developed some level of immunity against the virus – a positive sign that we are approaching closer to a functional end.

Signaling the return to normal life as we know it – one in which we are not living in fear of a virus that has an automatically higher mortality. But the functional end point is not the same as the epidemiological end point, which is defined by when we as a global population achieve herd immunity – the second though more uncertain variable to monitor.

Herd immunity somehow has become politicized in recent months, but its true epidemiological definition is straightforward – when enough of the population has acquired enough immunity to the virus to stop its active spread among the population. And while vaccine availability has made all the headlines, the more impactful metric determining when we will achieve herd immunity is whether we maintain social distancing guidelines and the use of face masks.

This makes sense when we consider herd immunity in terms of viral transmission or active spread. Herd immunity can be achieved by administering a highly effective vaccine that rapidly boosts immunity in the entire population – it can be achieved by adjusting our collective behavior to minimize the spread.

While we see the vaccine as a miracle panacea, we have to maintain realistic expectations that it will not be as effective as predicted and there will be significant logistical issues in the distribution of the vaccine.

Leaving the population with variable levels of waxing and waning immunity from the vaccine. Moreover, we cannot predict the duration of acquired immunity from the vaccine, which means the most predictable course of action in achieving herd immunity is to remain compliant with the social distancing guidelines.

We can project and predict to our heart’s content, but unless we account for the variabilities in our collective behavior, we will never know for certain how true the numbers will hold or how effective the vaccine will be once it is introduced into the more variable, dynamic population.

McKinsey & Company has compiled data from various sources including the CDC and World Health Organization and developed a probability adjusted model for when the functional and epidemiological end of the pandemic will occur.

We seem to be more confident that the convergence and stability of the case fatality rate will functionally end the pandemic for majority of the population, and life can resume back to normal by the beginning of summer in 2021.

But the epidemiological end point will not occur until closer to the end of 2021, possibly the beginning of the 2022, with the biggest factors being the vaccine efficacy, vaccine distribution model, and the natural and acquired immunity levels attained and duration of these levels. There are more questions than answers at this point, and more that is uncertain than certain when it comes to understanding how the vaccine will work outside of a controlled environment.

We know natural immunity waxes and wanes inconsistently across different populations, and we have good reason to be skeptical about the vaccine true efficacy when it is released into the population.

And for these reasons, we must place more faith on our ability to adhere to the social distancing guidelines throughout the first half of 2021, than the vaccine’s efficacy to instantly achieve herd immunity. As a result, the likely bet is that the pandemic will not be over from an epidemiological standpoint until late 2021 – and months after the pandemic is functionally over in the minds of the public.

Let us hope that we have the mental stamina to endure the pandemic for at least another six to nine months – because the sooner we cave into the COVID-19 fatigue, the longer the pandemic will last.