Simple social distancing and hand-washing could be what it takes to beat the spread of Covid-19
The first Covid-19 case in Bangladesh was identified on March 7, and at the time of writing this piece, the official count of infected stands at 44, and the death toll is five.
Bangladesh is arguably a bit “lucky” that it has come to the crisis, or the virus has come to us, later than so many other countries. As a result, we have now had more time to get ready, and can benefit from the harsh experience of others. What’s critical to note at this juncture though, is that it takes approximately one-and-a-half to two months from the first reported case for the viral spread to reach the peak number.
We can expect to see a much greater number of cases by the middle or end of April in Bangladesh. But given that we are a notably resource-deficient country, even a few thousand cases can push our health care system to breaking point.
And that means the case for containment remains as urgent for us as ever; there can be no letup whatsoever on social distancing and hand-washing, which are the two most effective preventive measures against this virus. Even the nation-wide quarantine may need to be extended by another week or two (and one can only hope no further).
The self-quarantine has proven a great challenge for our country so far, given the gregarious nature of our people. It is natural that any returnee from abroad would eagerly look forward to meeting their relatives, friends, and actually the entire village as soon as they land. Unfortunately, now is not that time.
The government declared a ten-day holiday not for socializing but for social distancing. No previous exposure, zero immunity, and no vaccination against Covid-19 makes each one of us vulnerable to contract the disease upon exposure.
Except for China, every other country had that one imported case that infected others locally and finally the disease spread through local community transmission. Statistical evidence from other countries explains that social distancing at this point is the major intervention that can help us blunt the expected exponential spike.
The next two to three weeks are the most critical for us, a full-on measure of social distancing may spare us from an Italy or Iran-like scenario. A third of the global population is under lockdown now to control the spread of this highly contagious disease. It is our duty as individuals to do our part and stop the disease at its track.
“Flattening the curve” is the ultimate goal in epidemiology o fa disease. What does it mean and how is it achieved?
The above graph is the basic principle to reduce the rate of infection and avoid inundating the limited resources of our health care system. The steep rise indicates a surge of Covid-19 cases, an overwhelming number beyond the capacity of a country’s existing health care system. In Italy, during this steep period there were 5,000 cases on average each day, in the US the number is 11,000 to 17,000 cases now each day; in China, on the worst day, there were 14,108 cases reported but the lockdown later on slowed the rate of cases.
The flatter slope indicates that the same number of people will get infected but at a slower rate, so that the health care providers can treat all cases without stressing themselves and the limited supply of resources. Intervention measures to reduce the contact between people can slow down the rate of infection that will potentially affect in lowering the number of deaths. Singapore, South Korea, Taiwan, and Hong Kong were successful in flattening the curve.
Executing a combined intervention of isolating infected individuals, quarantine of their family members, school closure, and immediate workplace distancing for at least two weeks is an ideal countrywide measure. But this scenario also requires availability of enough negative pressure rooms in large health care facilities for isolation, specialized ambulances, abundance of test kits to detect symptomatic and asymptomatic cases, and personal protective equipments (PPEs) for all health care providers.
For Bangladesh, the situation is less than ideal. A report published by the Health Ministry in 2019 stated that there are only 5.26 doctors and 3.06 nurses for every 10,000 people in this country. Another country index shows that, for every 10,000 people, we only have eight hospital beds. Number of critical care beds, ventilators, and other medical supplies are far from optimal.
If compared to Italy, that country’s doctor-population ratio is 3.8 for 1,000 people and nurse-population ratio is 6.1 for 1,000 people; in Thailand, the number is 2.28 doctors and 2.28 nurses for 1,000 people. Bangladesh has 164 million people -- what kind of disaster are we looking at if there is a sudden steep rise in the number of cases? And, if our front line workers themselves get affected without the protective gears, who will treat us?
The recent intervention by the government to achieve social distancing might actually work if people understand the full repercussions of their behaviour. There has been a massive influx of Bangladeshis returning from corona-affected countries like Italy, UK, China, US, Thailand, and others. The authorities have put them in 14-day self-quarantine period, which means they must remain in their homes and cannot step out for anything for those 14 days.
What is the importance of 14 days?
The coronavirus incubation period is 5.5 days. People will show symptoms of infection within 12 days of getting infected. Whether symptomatic or asymptomatic, infected people remain infectious, meaning they will spread infection for 14 days from the time they are infected.
That’s why quarantine of people exposed to the infection is 14 days. If they show symptoms of the disease, then until they are fully recovered, they must remain in isolation.
When fever and all symptoms like cough are gone and two consecutive tests within 24 hours for Covid-19 becomes negative, only then can they be released from isolation. In self-quarantine, the family members of these exposed people are also in quarantine.
Disregarding the 14-day quarantine period can result in disastrous situations. As it is, anyone already infected may have infected many others throughout the distance they had travelled -- in the flight, in the airport, in the cars, and in their homes.
Let’s dig a little deeper. The basic reproduction number, also known as R0(R naught) is the expected number of cases directly generated by one infected case in a population. For the case of Covid-19, R0 is important as it is a new contagious disease which makes everyone susceptible.
When R0 is greater than one, it starts to spread and has the potential to cause an epidemic and if it is less than one then the disease will decline and eventually die out. According to a paper in the Journal of Clinical Medicine, the R0 for Covid-19 is 2.49 to 2.63. That means one known case can infect on an average 2.5 more people.
Occasionally, there is also that one person who can transmit the disease to tens or even hundreds of other cases. They are the super spreaders and there is evidence of super spreaders in China, Italy, and the US. However, R0 also depends on the environmental condition, the behaviour of the infected population, and finally, how many in the population have already been affected.
Another study by CDC suggested that the serial interval of Covid-19, which is the time duration between a primary case-patient (infector) having symptom onset and a secondary case-patient (infectee) having symptom onset, is 3.96 days.
Now coming back to self-quarantine, no one knows how many of those returnees were infected, non-infected, asymptomatic, symptomatic, or super spreaders. We have to give them those 14 days from the day of landing to figure that out.
Why the need to maintain personal hygiene?
This virus is highly contagious and certain measures may help us defeat it. SARS-CoV-2 virus consists of three building blocks -- RNA, proteins, and lipids. The proteins help the virus break into the human cell and in the replication process.
The RNA contains the genetic material which, upon invading a human cell, takes over the cell’s activity to replicate its own RNA and the various proteins that make up the virus. The lipid is a bilayer and forms a coat around the virus to protect it and assist with its spread and cellular invasion. The viral self-assembly is based on weak “non-covalent” interactions between the proteins, RNA, and lipids.
New viruses replicated in the invaded human cell eventually overwhelm the cell, and it dies or explodes, releasing viruses that then go on to infect more cells. In the lungs, viruses end up in the airways and mucous membranes. Tiny droplets of cough or sneeze of an infected person can fly up to 30 feet.
The larger droplets are thought to be the main coronavirus carriers, and they can go at least seven feet. Therefore, it is important to cover one’s mouth during coughing and sneezing.
The virus survives on different surfaces. It was detectable in aerosols for up to three hours, on the surface of copper up to four hours, cardboard up to 24 hours, and plastic and stainless steel up to 72 hours. It interacts more strongly with organic substances like wood, fabric, cardboard, and skin.
Steel, porcelain, and plastics have smooth surfaces where the virus is less sticky and upon touching these surfaces the virus is transferred to our hands. But this does not necessarily mean that a person can get infected from touching these infected surfaces.
The levels of the virus concentration on the surface and its half-life are important factors for causing infection and scientists still don’t know how high a concentration is needed to get someone infected.
However, there are still chances of getting infected when we touch our nose, mouth, or eyes after touching a contaminated surface.
The lipid coating of the virus has hydrophobic and hydrophilic ends. Soap contains fat-like substances, structurally similar to the lipids in the virus membrane. When we wash our hands with soap, the soap molecules “compete” with the lipids in the virus membrane.
The soap and water dissolve the glue-like bond between the virus and skin surface, tugs on the lipid membrane of the virus and ruptures the bond, destroys it and washes it away. As skin is rough and wrinkly, a fair amount of rubbing and soaking ensures that the soap reaches every nook and cranny on the skin surface that could be hiding active viruses.
In the absence of soap and water, 60%-80% ethanol-based hand sanitizer’s alcohol can also dissolve the lipid membrane and destroy the virus.
One thing is established though, most common mode of transmission via respiratory secretions happen in the form of large respiratory droplets. Aerosolized transmission occurs most likely in health care settings while using nebulizers in infected incubated patients that create a mist in which the virus remains suspended in the air. It is advisable to use only metered dose inhalers at home settings.
It is now self-explanatory as to why experts are asking every individual to follow the personal safety measures:
1. Cover mouth with a tissue while sneezing, coughing, or blowing one’s nose.
2. Dispose the tissue and wash hands immediately for 20 seconds with soap and water or use hand sanitizer containing 60% alcohol.
3. Do not touch mouth, nose, or eyes with contaminated hands.
4. Avoid sharing personal household items.
5. Maintain personal hygiene regime and wash hands after going to the toilet, when hands are visibly dirty, before eating, before cooking, and after coming home from outside.
6. Clean doorknobs or frequently touched surfaces with disinfectants during this outbreak for further precaution.
7. Masks must be used by infected people, people in contact with infected people, and immunocompromised people.
8. Avoid any congregation of people.
As Bangladesh enters into the community spread where the virus is spreading in new areas and people are not sure how or where they became infected, we do not have a choice but to remain vigilant.
Instead of debating about the whys, it’s time for collaborative effort from our part and abide by the protocols and maintain social distancing, report to the authorities if there are symptoms, educate each other, and take care of the elderly.
There are few things in favour of Bangladesh -- the population demography shows that around 12% of our entire population is above the age of 60, and 88% are below 54. It is a country of the young and even though the virus does infect people of all ages including children, it causes more serious symptoms in the elderly and immunocompromised.
Also, according to US CDC, generally coronaviruses are less stable and survive for shorter periods of time at higher temperatures, strong sunlight, and higher humidity than in cooler or dryer environments. For Sars-Cov2 virus, there is no direct data for a temperature-based cutoff for inactivation at this point but since we are heading towards summer, we can definitely hope that its survival depends on temperate conditions.
Bottomline, please maintain social distancing the next 14 days or start calculating your days from the day of your arrival or coming in contact with an infected person. Remember, this virus needs a host to survive, and the trick is to not let it get to us.
Every life counts and we can get through this together.
Dr Maliha Mannan Ahmed is an entrepreneur and healthcare specialist.