Notes from the coronavirus war zones

The Covid-19 pandemic rages on, hitting cities in Asia, Europe and the US. Possibly in waves. Most of us are now used to the daily pouring of numbers about the pandemic. The number of new testing, infection cases, recoveries and deaths, together with cumulative figures, along with their geographical and demographic distribution, are reported all over the world. 

These feedback from the war zones have established Covid-19 as a highly contagious virus that has attacked rapidly and efficiently. It sneaks invisibly through direct contact with the symptomatically or asymptomatically infected person's coughing and sneezing, as well as contact with infected surfaces where the virus survives for days. A simple disinfectant can kill it on physical surface, which misled Donald Trump a little too much to engage in some damaging musings in public.

No place seems immune. Starting from China, the virus appears to be competing with Genghis Khan on waging the most gruesome and brutal warfare against the human race. It has invaded 210 countries, infecting over 3.1 million and killing more than 210,000 already. Europe accounts for nearly 58 percent and US accounts for about a quarter of global deaths so far. The virus has no respect for wealth per se! It has perforated all conventional defense systems and compelled the world population to hide in their homes and behind their masks. It has instilled a fear deep in our minds that the dear old next-door neighbor may inadvertently have turned into the worst enemy! 

Will the virus be a little less menacing in its warfare against us, the South Asians?

Covid-19 came late in South Asia. Confirmed deaths per thousand population and confirmed cases per thousand tests in South Asia are order of magnitude lower than Europe and the United States. South Asia's high population density makes one expect a substantially larger share of residents to be infected than in sparsely populated countries because of the possibility of frequent interpersonal contacts. Yet, if you look around, some extremely dense cities, such as Singapore, Seoul, and Shanghai, have outperformed many other less-populated places in combating the coronavirus. 

Strategic use of the advantages associated with higher densities can reconfigure interpersonal contact in high density environments. Due to economies of scale, cities often need to meet a certain threshold of population density to offer higher-grade facilities and services to their residents such as convenient high-speed internet and door-to-door delivery at competitive prices. Availability of these services makes it easier for residents to stay home and avoid unnecessary contact with others. Singapore and Seoul have demonstrated that density under such circumstances can be turned into a fortress in the fight against the coronavirus if a coherent set of mitigation measures kick in early enough. 

Bangladesh seems to have one of the lowest death rates per thousand infection so far despite overburdened hospitals. Reported deaths data have several problems. The actual total death toll can be understated due to limited testing and problems in the attribution of the cause of death. These are universal problems that only vary in degrees between countries. Such caveats notwithstanding, the fatality rate in Bangladesh is relatively low. 

The age and gender distribution appear to be good variables for tracing explanations. The older people are at much higher risk of dying. Most country level data, including Bangladesh, shows that mortality rates increase steeply with age. These data also show higher death rates among men. Such a reversal of gender bias seems to repeat itself, albeit in slightly different numbers, in country after country. Bangladesh is no exception. Women appear to be much more valiant fighters of Covid-19 everywhere for reasons researchers are still struggling to nail down.

Infection data suggest limited aggression of the virus so far. Bangladesh has low, but rising, confirmed cases per thousand tests. This has a lot to do with limited, again rising, testing of symptomatic individuals approaching health facilities having testing capacity. It misses people who have symptoms but cannot get tests done and people who are asymptomatic. Testing so far has also been geographically concentrated. 

The strongest evidence of low testing is the elasticity of the number of infected cases to the number of tests. Based on first 49 days of recorded data (till April 25), the elasticity of the cumulative number of infected cases to the cumulative number of tests is 1.28. This suggests that a 10 percent increase in the cumulative number of tests increases the cumulative number of infected cases by 12.8 percent. More we test, more and more infections we find.

It is not possible to win a war against a contagious virus without a vaccine. Until then, all that mankind can do is to adapt to the biology, chemistry and physics of the virus. The tools needed for adaptation are a health system capable of managing disease cases and virus carriers, sanitization capabilities and social distancing.

Low capacity of the health system in Bangladesh is manifest most glaringly in low recovery rate. The recovery rate (2.3 percent of infected cases) is in fact lower than the death rate (2.8 percent), a unique feature. Hospital, especially intensive care unit capacity and overall quality of care is key. A substantial part of the mortality occurs when the number of cases in need of intensive care exceed existing capacity. There are many other questions. Do people actively seek treatment? How easy is it to get to hospitals? Do people have to pay to be treated well? No, difficult and yes appear to be respectively plausible hypotheses, if not facts.

Ensuring universal access to water supply, sanitation and hygiene has been a major challenge for Bangladesh. Covid-19 has created additional demand for the provision of safe water, sanitation and disinfection products and services across a wide range of premises. Government, the private sector and communities need to take unprecedented precautions to keep themselves and their homes, offices, schools, and market places clean and disinfected to help reduce virus transmission. Brac's deployment of their 100,000 staff and volunteers to visit 5 million households and distribute 1.5 million stickers and leaflets mainly in rural areas along with a large mass media campaign and the response of Bangladesh's print and electronic media have complemented the government effort to promote public awareness of Covid-19 preventive hygienic practices. 

Social distancing is incongruent with the economic realities and cultural ethos in Bangladesh. The rate of social mixing between people and crucially the rate of mixing across generations is high. Several generations live in the same household. A large number of the poor and vulnerable live in dense communities, of which urban slums are extreme cases. Instances of major lapses in physical distancing in factories, marketplaces and public relief distribution abound on a daily basis. 

The rate of social mixing and physical proximity determine what epidemiologists call the virus reproductivity rate, R-naught (R0). This is the average number of people infected by each infected person. In the absence of any mitigation measure, it is currently estimated to range between 2.4 and 3.3, depending on demographics and comorbidities. The containment measures try to reduce this number to below 1. One would expect a high R0 in Bangladesh not only because of high rate of social mixing and congested living, but also because of weak and uneven enforcement of physical distancing in public places. God forbids, perhaps the worst is yet to come! 

How can we do better on adaptation? Ideally, we would like to know how different sets of containment measures affect the scale and the trajectory of the disease. This will help customize and scale up the ones that have produced the best results. Moderating spread of an indomitable virus while minimizing the economic costs such moderation imposes is a challenge mankind has never faced before at a global scale. 

The best weaponry for fighting the virus comes from science. Comprehensiveness and reliability of data to customize response systems is critical. Without a safe and effective vaccine or medicine, reducing viral transmission is the only strategy available. This can be done with early detection and patient quarantine, appropriate sanitization, general education, and minimizing person-to-person physical contact. Universally prescribed hygienic practices and social distancing measures are helping flatten the virus spread curve in shifting epicenters. 

Yet, there are many unanswered questions. 

Are halfhearted lockdowns worse than no lockdowns, given that the former imposes economic costs most heavily on those who can least afford it while not necessarily containing the spread? How long do we have to carry on like this, knowing that a vaccine will not come, if it ever comes, before 12 to 18 months? What is the optimal sequence of exiting the lockdown?

Can we count on herd immunity, given our 26 years of median age? The chaotic manner in which our garment factories are reopening suggests they are betting on it. Scientists, however, do not know for certain whether the human body even develops immunity after a Covid-19 infection. If the body does become immune, there's inconclusive evidence on how long immunity to the virus might last after recovery. Experts believe it is likely that someone infected with Covid-19 will have some level of immunity after recovering from the illness, but the details are still sketchy. Results from the ongoing grand Swedish experiment are not in yet. 

Can heat and humidity be a reliable ally in this war? The evidence appears unconvincing either way. Because the virus is novel, researchers are still learning about it on a daily, basis. The Centers of Disease and Control and Prevention says it is "not yet known whether weather and temperature affect the spread of Covid-19." Harvard researchers agree: "Summer may not save us, and repeated periods of social distancing may be needed to keep serious cases from overwhelming the hospital system". However, an MIT study which looked into global cases of Covid-19 from January 22 through March 21 is more hopeful. They find that the virus was not spreading as rapidly in warm and humid climates. Few other studies on Southeast Asia also observe that the spread of infection has been a little bit slower in some of the hotter countries than in the cooler countries.

Changing seasons may help but are unlikely to stop transmission. The invisible enemy may go on a tactical retreat when weather heats up beyond its tolerance level, but it probably knows when summer slows its rampage, winter is only a few months behind!