The predictability of a pandemic

The three Cs: closed spaces (such as restaurants and gyms), crowds (such as those seen in congregations of people for recreational, religious, political and other social reasons) and close contact (such as public transport) account for a majority of infections, says Dr Pinto.

I am a respiratory physician who has been treating patients with Covid-19 for the past 16 months. While certain patterns have emerged which help triage patients, there is still little understanding as to why some patients deteriorate while others don’t. This is frustrating, because it makes it difficult to decide whom to confidently reassure, and whom to help brace for a stormy course ahead.

People walk through a crowded market on a rainy day amidst the spread of the coronavirus disease in Mumbai (REUTERS)

In contrast, as an epidemiologist, I feel confident in knowing that the signals from a public health perspective have been fairly consistent to prevent the spread of Covid-19.

Whether it was the potluck banquet for the Lunar New Year at Wuhan, China in January followed by an exodus of 5 million people from the city for the holidays or the football match at the San Siro stadium leading to Bergamo being the epicentre of the first wave in Italy in February 2020, or numerous instances since, overcrowding has consistently facilitated the exponential spread of the virus.

The three Cs: closed spaces (such as restaurants and gyms), crowds (such as those seen in congregations of people for recreational, religious, political and other social reasons) and close contact (such as public transport) account for a majority of infections.

With more transmissible variants such as the Delta, such “superspreader” events are even more likely to be the drivers of future spread.

The investigations conducted by HT on the high incidence of infections in certain districts of Maharashtra arrive at similar conclusions. Elections and rallies leading up to them appeared to be a driver of spread. Congregation of crowds of at tourist destinations was another. An over-reliance on Rapid Antigen Test kits (which are prone to detect around 50% of those infected) meant that infected people were escaping the net, thereby continuing to spread the virus.

As vaccines were in limited supply, prioritisation of vaccination of the elderly, whilst protecting the most vulnerable, may have led to the under-protection of the most exposed workforce, leaving them vulnerable. Most importantly, economic hardships have left individuals with no choice but to resume work, despite being cognisant and fearful of the risks entailed. All of these, based on our understanding of spread over the past year, were preventable.

How can we change this?

It cannot be emphasised enough that the workforce needs to be vaccinated on a priority basis, and we have not done this at a pace that we should have. This is especially needed in areas of essential activities such as grocery stores and marketplaces, where the sheer magnitude of the population will make it impossible to avoid crowds.

One cannot expect individuals to behave in a way that is detrimental to their livelihood, and shaming or penalising them has almost never been a successful strategy. We have not focused enough on the economic safety nets and financial support from employers and the government that would enable individuals to refrain from engaging in risky behaviours. It will be worth considering mandating vaccination for recreational activities (restaurants, gyms, tourism, sporting events), which would boost vaccine uptake especially in the private sector, in which shortages do not seem to be as much a concern.

Preventing crowds from aggregating for events, whether political, religious, or social will be more challenging, despite lockdowns in place. Focusing on harm reduction is likely to yield more dividends than attributing blame. While the government needs to strictly prohibit mass gatherings, we will need to think of innovative ways to dampen the effects of such events if they do occur. For example, encouraging masking and preventing sloganeering and chanting (speaking loudly can increase droplets 50-fold, and singing, almost 100-fold) at such events could all potentially reduce the probability of spread.

“Cluster-focused backward tracing” — which was used with success in Japan — tracks every case to a likely superspreader event and then tests those present at the event, rather than forward tracing, which focuses on those who came into contact with the person post-infection.

The uncertainty around the nature of the course of the illness once infected, versus the predictable nature of spread, suggests that we need to invest all our resources into preventing disease and overburdening the healthcare system. Doing this, while acknowledging the need for social interaction and earning one’s livelihood, in the most non-judgmental way, would determine our future success in containing this pandemic.

Dr Lancelot Pinto is a pulmonologist and an epidemiologist