• Wednesday, May 27, 2020
  • Last Update : 01:08 am

At the steep part of the curve

  • Published at 12:44 pm April 4th, 2020
Covid
Testing early is crucial

Bangladesh does not have the right resources to face this crisis, but we have the benefit of being able to learn from other countries

On March 1, the total number of worldwide Covid-19 cases was 88,585. Now, after a month the reported number of cases has crossed a million. We saw the epicentre move thrice -- from China to Italy and now the US and Spain. 

If we look at the worldwide trend of the disease spike, it is evident that we are somewhere on the steep rising curve now. It is difficult to predict what more mayhem this virus can cause as Africa and South Asia still await a surge.

Every country is managing their outbreak with their available resources and this pandemic has proved that barring a few, no country has the optimal resources needed to fight this war against the virus. Bangladesh unarguably falls in the bottom of the tier in terms of available resources. Fortunately, we have had the benefit of time to observe and learn what the developed countries have done to slow the rate of this disease. 

WHO’s strategy – “detect, test, treat, isolate and trace contacts” has had positive impact in lowering the rate of infection in some countries. In South Korea, the disease-control authorities set unprecedented examples in testing and receiving results of thousands of people within a day from a network of labs, designed maps of movement of people, and encouraged infected people to trace their contacts.

The initial overwhelming numbers at the hospitals soon declined when milder cases were managed from home. Singapore went one step forward in chasing the missing link between two clusters by doing a serologic antibody test for Covid-19 weeks later and identified the suspected case. Germany followed South Korea and has a mortality rate of 1%, whereas its neighbouring countries Italy and Spain have a rate of 11.7% and 8.75% respectively. 

The Bangladesh government declared a public holiday till April 11 and is enforcing people to maintain social distancing. As of today, the total cases in the country stand at 61 with six people dead, making our death rate an alarming 10.71%. The actual number of infected cases can only be detected through testing, which will reflect the percentage of milder cases, severe cases, and the actual death rate against that. Extensive testing will not only identify clusters that need isolation but also generate transparency, reduce fear, and speculation. 

Why is testing so important?

The viral concentration at different stages of the disease and the duration of viral shedding is an important marker of the disease prognosis, disease spread, disease outcome, and duration of isolation. Two retrospective case studies with definitive clinical outcome published in The Lancet stated that the average duration of viral shedding from all confirmed Covid-19 cases is 18-20 days. 

People having a mild case of Covid-19, if diagnosed within the first two days of symptom onset, will show a high concentration of viral load in their upper respiratory tract (nasopharyneal swab) samples. This is suggestive of potentially high risk of transmissibility. Viral shedding from these cases drop after five to nine days.

Some cases had milder symptoms on admission but in 10 days turned severe requiring ICU support for respiratory difficulties. These cases were tested and diagnosed five days after the onset of symptoms and the specimen collected from the nasopharyngeal swab showed less viral load at that time. However, the viral shedding continued till the symptoms abated.

Critical cases with severe multi-organ complication showed high viral excretion from the upper respiratory tract samples throughout the course of illness. In such cases, the virus was also detected in the blood and the pleural effusion fluid. 

The studies emphasized on testing as soon as there is symptom onset. Not only is the viral load highest in the nasopharyngeal specimen during the early phase, collecting the specimen is also easier. There is also evidence that even after full resolution of the disease symptoms, low-level viral load persists in the upper respiratory tract in some cases. 

This prolonged viral presence means that the patient may remain infectious to others. The European Centre for Disease Prevention and Control recommend that a patient should only be discharged when two swab tests done 24 hours of each other detect zero viral presence. 

Different therapeutic approaches are required for patients with a lower viral load in the upper respiratory tract versus those with high viral replication and systemic virus dissemination.

Viral shedding is a determinant of how many days a diagnosed Covid-19 patient must remain in isolation. 

Testing early will lead to early isolation, reduced spread, and quicker medical intervention for improved patient outcome. As some cases in the study were the family members of the primary infected cases, it reinforces the importance of contact tracing and quarantine of those exposed. 

What are symptoms of Covid-19?

A study based on 70,117 laboratory-confirmed and clinically diagnosed cases in mainland China published by Imperial College London estimates the fatality rate to be 1.38% in confirmed cases across all age groups; this is supported by an earlier report by Harvard University. 

The study further stated the age specific differentiation for hospitalization requirement: 12% of people in their 60s, 8.2% of 50-somethings, 4.3% between 40 to 49, 3.4% of 30-somethings and 1.1% of 20-somethings confirmed Covid-19 patients required hospitalization.

It is most fatal for people over 80 with comorbidities. Median age of most affected people is 56 years and 80% affected will show mild infections. Even though prognosis for the elderly is poor, some severe cases among the young may require ventilator support for a short period. 

Some 81% of cases that are mild may have no pneumonia or mild pneumonia, mild fever, cough (dry), sore throat, nasal congestion, headache, muscle pain, shortness of breath (SOB), or malaise.

Severe cases requiring admission may come with fever, cough, severe SOB, respiratory distress, increased respiratory frequency ≥ 30/min with lower oxygen saturation≤ 93%. Chest x-ray, CT scan, or lung ultrasound may show bilateral opacities and mechanical ventilation may be required with ICU support. 

Critical cases may have respiratory failure, septic shock, and/or multiple organ dysfunction (MOD) or failure (MOF). These cases are associated with pre-existing comorbidities like hypertension, diabetes, heart disease, asthma, or immune-deficient conditions. 

Emergency doctors in the developed countries are using Sequential Organ Failure Assessment (SOFA) score for prognostic value of the cases.

They detect that cases over 80 with comorbidities, having a higher SOFA score and presenting with greater d-dimer which indicates increased coagulation activity, have very poor prognosis and may result in death.

What are the diagnostic tests for Covid-19?

There are two types of molecular tests (PCR and RT-PCR) to confirm Covid-19. With samples collected from upper and lower respiratory areas, these tests detect signs of the virus’s genetic material. The test will give a positive result only in active cases where the virus is still present. It will not identify people who have had an infection, recovered, and cleared the virus from their bodies. It is a sensitive test and must be done by trained people starting from proper collection till the reading of the result to avoid false negative result.

The serological tests detect antibodies the body produced against the virus and is done weeks after a patient has recovered. It is useful for identifying the asymptomatic and mild cases. Serosurveillance in future will be needed to measure population immunity against Covid-19.

"This pandemic forced us to take stock of our own inventory. Right now, private and public collaboration is essential to increase the capacity"

Abbott Laboratories recently got FDA approval to run their five-minute rapid Covid-19 test designed for doctor’s offices and smaller hospitals without complex testing labs. The device can generate positive results in as little as five minutes, and negative results in about 13 minutes.

The costs of increased testing, contact tracing, and self-isolation are high in the short term for any country. In the longer term, however, more rapid control will reduce the economic and social costs of social-distancing measures that adversely affect businesses, communities, and individuals.

Why is Covid-19 so fatal for older patients?

The reaction to the virus is dependent on a person’s immune system and to the timespan the person remained exposed to the virus. The data so far available seems to indicate that the viral infection is capable of producing an excessive pro-inflammatory immune reaction in the host. 

Older people with comorbidities may have vulnerable immune systems where excessive cytokines produced by the activated leukocytes to fight the virus may end up causing extensive tissue damage. It may promote growth of some categories of cells and inhibit the growth of others. 

It is important at this time to take immune system balancing food, supplements, vitamin C and D, zinc, and drink lots of warm fluid.

Can Bangladesh use the digital platform to help citizens?

As the whole world moves toward virtual workplace and virtual learning, the health care system needs to attend to their patients through virtual consultations. 

Bangladesh has 90.5 million internet users and 84.6 million of them access the internet from their mobile phones. 154 million out of 160 million of our population are using mobile phones. This rich digital connectivity can be used now as an alternative for patient counselling. 

The multiple health care start-ups, telcos, and the social media apps have video conferencing tools which can be used in this time of emergency to set up doctor-patient virtual counselling. If an outbreak happens, the health care providers at the frontline in the emergencies, critical care units, and wards will require additional resources. 

At that time, tele-medicine can be an excellent opportunity to utilize non-internal medicine specialists, medical officers, fourth and final year medical students, and other medical workforce to ease the burden of the front liners managing the Covid-19 cases. 

Information gathered from the hotline number #3332 can be filtered under proper guidelines set by the authorities and medical care can be targeted for suspected Covid-19 cases. The internet can also be used innovatively to track the hot spots within the country for further monitoring and isolating. mHealth is already being used to share Covid-19 related information with the citizens, it can be further used to engage with patients not requiring emergency medical attention. 

We are studying demographics to predict the number of people at serious risk and hoping higher temperature may weaken the pathogen, but the reality is -- we don’t know. If the disease follows the typical trend in Bangladesh, then by the third week of April we could expect to see a surge of cases. 

However, the trend also shows that the disease is creating havoc in densely-populated cities where lockdown was enforced much later. The government-imposed social distancing in Bangladesh early on will definitely lower the transmission and if rapid testing begins, we can hope to also detect the maximum number of already infected cases by middle of April. 

This pandemic forced us to take stock of our own inventory. Right now, private and public collaboration is essential to increase the capacity to provide temporary critical care facilities, provide safety measures for our health care providers, make hundreds of thousands of test kits available, and increase awareness to not self-medicate upon hearsay. 

It is also glaringly evident that our health care system needs massive capacity-building to distribute equitable health services, improve health care delivery, and build a health data integration system. Otherwise we will always remain vulnerable to threats, like the one we face today. 

Dr Maliha Mannan Ahmed is an entrepreneur and health care specialist. 

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