For future historians, the most memorable event of the year 2020 is certainly likely to be the Covid-19 pandemic, followed by the US Presidential elections. One does not have to stretch one's imagination to see how intertwined these two phenomena are since the question on everyone's mind is, "Are we getting the vaccine before Election Day?" This question, which epitomises the crux of the current national debate in the realms of politics, economics and social discourse, is also the trigger point for all sorts of uncertainty and hopelessness about the future.

The answer to the question I pose in the title of this commentary is not just a matter of speculative fantasy but will shape the future of both US politics as well as the path of the war against Covid-19.

If you were to ask, "When do we get the Covid-19 vaccine?", the average person might respond, "who knows?" However, most epidemiologists would say, "I am not sure we'll have one soon! But, before Election Day, November 3, it is possible but not likely." What does that mean? When I asked this question to Imran Hussain Chowdhury, MD, an infectious disease specialist, he was skeptical about the prospect of having a safe and proven vaccine before the end of the year. As a physician with the Infectious Disease Care Center, he is preoccupied with treating his patients in the Greater Washington DC area and is trying to focus on the job at hand: testing and treating the sick. Dr Chowdhury cautions that the vaccine development process takes time and while modern technology can help, the safety and efficacy of a vaccine must be given the highest priority.

The complexity surrounding the development and deployment of the Covid-19 vaccine is quite significant and to make matters worse, the political leaders and policymakers have thrown in a mish-mash of terminology that baffles even the experts, not to speak of the non-specialists. Public officials are often reluctant to give straight answers and use words such as "likely", "possibly", and "probably", which are vague and not helpful.

There is already some bad news from the frontline. On September 8, AstraZeneca announced that it had temporarily stopped Covid-19 vaccine Phase III trials due to illness of one or more participants. The AstraZeneca vaccine, developed in conjunction with Oxford University, has been described by the World Health Organization as probably the world's leading candidate and the most advanced in terms of development. According to news sources, "The suspension dims prospects for an early rollout amid some reports that the United States was aiming for an October or November delivery."

In economics, which is adept with dealing with risk and uncertainty, we can handle any forthcoming event that has more than one possible outcome as long as we know the probability of the outcomes. However, for the man in the street, nothing is more baffling than the concept of probability. For example, if you know that the vaccine against flu is only 40 percent successful, would you take the flu shot? The answer is no, as reflected in the statistics for last year, which shows less than half the population in the USA got vaccinated. Nonetheless, the Center for Disease Control (CDC) strongly recommends that everyone should get a flu shot every year regardless of the statistics.

The CDC estimates the burden of flu and the impact of annual flu vaccination in the US using a model that estimates the numbers of flu illnesses, medical visits and hospitalisation prevented by vaccination. One control trial conducted with adults aged 60 years and older reported a vaccine efficacy of 58 percent. According to the latest data for the entire population, vaccine efficacy is 29 percent in 2018-2019.

Coming back to the topic of Covid-19 vaccines, President Trump officially launched Operation Warp Speed (OWS) on May 15, 2020 to develop and deliver 300 million doses of a vaccine for Covid-19 by January 2021. Dr Moncef Mohamed Slaoui, a Moroccan-born Belgian-American researcher, is the chief adviser for OWS. He called the time frame given for the vaccine development "very aggressive" but "achievable". On September 3, when asked if he thought that there would be a vaccine before Election Day, which was then less than eight weeks away, he said, "I think it's extremely unlikely but not impossible, and therefore it's the right thing to do to be prepared in case." Slaoui's careful choice of words, "unlikely but not impossible" has added a lot of fire to the political debate on Trump's election strategy. As expected, the Democrats are crying foul and taking all possible precautions for the three possible outcomes of the "vaccine lottery": an announcement in October that the vaccine is ready, an announcement that the vaccine is ready but not for immediate use, or that vaccination will proceed on a very limited scale.

The future is always uncertain. You take whatever tomorrow may bring. Is the weather tomorrow going to be good? No one can tell with certainty, but that does not prevent us from planning for our day tomorrow. Who could have predicted even six months ago that we would still be in the midst of the pandemic in mid-September? Therefore, the bottom line is, we manage to live with uncertainty.

As we navigate the Covid-19 quagmire, what can we expect tomorrow? We are all unanimous about our national goals: vaccine, tests, therapeutics, jobs and income. If we do not have a vaccine that is 100 percent effective, we can't have faith in it. But can we be certain that even a simple test is 100 percent accurate? No drug company will claim that theirs is.

In any basic undergraduate class in statistics, we learn the concepts of false positive and false negative results. These terms have now become part of everyday lingo. Patients die even after testing negative (a case of false negative). And there is an abundance of false positive cases too. On September 8, my home state, Massachusetts, suspended a coronavirus testing lab after 400 false positive cases were identified.

Professor Nassim Taleb of New York University popularised probability and helped the average person to start living with the concept of uncertainty, particularly low probability events which do happen. An example of this is the economic slowdown in 2008 and the current pandemic. Probability as we all know is not a black and white sphere. Events are both possible and impossible at the same time, depending on what the probability is and the nature of the event is. If you get a flu shot, are you likely to get the flu? Of course, you are. The flu shot is not 100 percent effective and that means that even if you are vaccinated for the common flu, you still might catch the flu. At least the CDC is candid—"Everyone can make their own decision based on available information."

During my graduate studies at Boston University, I took courses with a world-famous economist, Paul Rosenstein-Rodan. He gave us a very entertaining example to hammer in the distinction between probable and possible outcomes, or rather the impossible and the improbable. Paraphrasing Dante's Divine Comedy, Prof Rosenstein-Rodan told the story of a king in Greek mythology, who after being overthrown by a mass uprising, was offered two options: Be hanged by the neck or commit a harakiri by self-guillotining using a sword. The king went for the second option and walked for 2,000 yards with his severed head in his hands. Prof Rosenstein-Rodan told us that while self-execution was not impossible (non-zero probability), there was a zero probability that the king could walk holding his head.

Enough of this doom and gloom. Let me end this note with some good news. The chances that we will have a vaccine by the end of next year is high, i.e. the probability of success is 100 percent. Moreover, the grip of the virus will be substantially diminished by then.

Dr Abdullah Shibli is an economist and currently works in information technology. He is also Senior Research Fellow, International Sustainable Development Institute (ISDI), a think-tank in Boston, USA.