COVID-19’s rapid spread caused by super-spreaders – Dr. Mahen Kotalawala
By Akila Gunasekara
Dr. Mahen Kotalawala, a Clinical Microbiologist and Infection Prevention Professional, who works at the Kandy General Hospital, has written to President Gotabaya Rajapaksa, explaining the steps needed to be taken to control the fast spreading COVID-19 in the country.
Following are excerpts from an interview with Dr. Kotalawala.
How do you interpret this pandemic?
A: Initially, COVID-19 spread in our country slowly. One patient spread the virus to a few people. Generally, one person carries the virus to two more persons but in Sri Lanka it was 1.1 persons as an average. However, we see one person is carrying the disease to five or six persons this time. Unlike the previous time, there are super-spreaders among us.
The nature of the epidemic can be mathematically explained when considered facts like the time taken to double the number of cases. There are four ways of the spread of this epidemic. They are the Lag Phase in which the spread is slow, Exponential Phase in which we see rapid growth within a certain period and the Stationary Phase in which the epidemic spread is stable.
We are now in the Exponential Phase. Many countries could not control the epidemic in this phase.
How did it spread so fast?
A: That question cannot be answered without a scientific study. But we can guess that several infected persons have had wide social association. We noticed a similar situation in Welisara Navy Camp also. The spread was faster there too. There were super-spreaders. However, Navy is an organised structure and they could control the situation without letting the disease to spread into community. All the personnel were called back to the camp.
The unmasked persons who are around an unmasked infected person with a distance less than one metre can be exposed to the virus through loud-speaking, cough and sneezing. Five minutes is enough for a career to spread the disease to three persons around the infected person. We can imagine what could have happened in Brandix factory. There might be many infected persons. They said that they had been working while taking painkillers.
That is why we are repeating the messages on social distancing.
What is the reason for Peliyagoda fish market cluster spreading faster than Brandix cluster?
A: A fish market is a crowded place. The culture is also different there. They speak aloud and that too can help the spread.
Similar things happened in other countries as well. A lead singer in a church choir in US spread the virus to 30 of the 60 vocalist choir unknowingly that he was infected. It was 50%.
What is the pandemic situation in Sri Lanka now?
A: We are in the Exponential Phase in which we can see rapid increase of cases within a brief period. If the situation continues, it will be uncontrollable. There are factors that decide whether this is further spreading or not. If those factors are fulfilled, we will be in trouble. We must act to prevent it.
Can we control the situation with the measures undertaken presently?
A: I propose the strategy change entirely. We must change the prevention, diagnosis and awareness strategies.
What do you propose?
A: We cannot achieve zero quickly in an epidemic like this. However, we can minimise the spread. If we follow a strategy equally throughout the country, we can control the disease extensively. What we can do at this stage is diagnosing the cases immediately and quarantining them.
We use PCR tests to diagnose the cases. It is the best method, but it is unaffordable to us now. PCR is too much for the requirement. It is like using a BMW to run a taxi.
Our strategy since the beginning was tracing the patients and the associates through PCR tests and quarantining them. It was alright at the initial stage because the cases were few then. But, now we diagnose hundreds of cases daily. We have practical issues like a lack of hospital beds. We need about 5,000-6,000 PCR tests carried out daily. It is very costly, and the tests delay. The person associates others during the period between the PCR is tested, and the report is received. If the person is positive, he or she might have spread the virus to many others. Earlier, we received reports within 24 hours. Public Health Inspectors and Army took necessary actions fast. When the number of cases is high, there are practical issues.
What is the alternative you propose?
A: This test is called the Lateral Flow Antigen Test in which the protein antibodies in the infected person’s blood is tested. It is a low-cost field test that brings results faster.
What are the alternative prevention measures you suggest?
A: The messages communicated through Media seems unproductive. If people followed the actions like keeping one-metre distance, washing hands and wearing masks, this spread might not occur. We must change the awareness strategy too.
So, what must we do now?
A: Stay at home and go out only when it is essential. Do not hide the disease, report it. We must minimise socialising. People have not understood this message properly.
We must avoid large groups attending functions like weddings and funerals if we want to prevent the spread of COVID-19. The capacity of isolating the infected persons and quarantining them have now been exceeded. We have to change testing, isolation and quarantining.
Most of the infected persons do not show any symptom. Do you have any calculation regarding showing and not showing symptoms?
A: According to medical records, about 60-65% of patients do not show any symptom. Another proportion shows minor symptoms. Some other people have severe symptoms while a few fall critically ill. Deaths are few. However, cases with mild and severe symptoms are high. Now, all these patients are hospitalised. Still, we can manage it, but if the number of cases further grow, our capacities will not be sufficient. Therefore, we must hospitalise only the critical cases while the other patients must be separated from society. The previously used quarantine centres can be used for this purpose. The quarantine can be done at home with the support of voluntary groups.
There is a social view that Sri Lankans are better immune, and as a result, the cases taken into ICUs and the deaths are low.
A: We still do not have scientific evidence to arrive at such a conclusion. The spread was slow initially, and the patients were better treated. However, we cannot say the rate of deaths is low. Out of 4,000 passengers of Ship Theodore Roosevelt, 1,500 were infected with COVID-19. Two third of them did not show symptoms. Only one third showed symptoms, while a mere one death occurred. The death rate is far lower there.
The immunity is essential. Still, the majority of the COVID-19 cases in Sri Lanka are comparatively young. The disease spread in elders’ homes in other countries, and a considerable number of older people died. The world experience is that the death rate of COVID-19 among the people over 80 years is 20%. The death rate for people above 60 years is 12-13%. Therefore, we must be careful not to carry the disease to the others. I want to emphasise, stay at home. Don’t associate even in the neighbourhood unnecessarily. If you feel ill, don’t hide it, report it to the health authorities.