How epidemics start and end: COVID-19 spread in PH analyzed
Published May 23, 2020 12:00 am
By Ellalyn De Vera-Ruiz
Dr. Mary Grace Dacuma of the UP Pandemic Response Team has released findings from a recent study on how an epidemic happens and what an epidemic wave is.
People stand on designated spots to maintain social distancing at a market during a government-imposed enhanced quarantine as a preventive measure against the COVID-19 novel coronavirus in Manila on April 21, 2020. (Photo by Maria TAN / AFP / MANILA BULLETIN)
She noted that the COVID-19 epidemic in the Philippines most likely started with an imported case from an infected person or persons who entered the Philippines.
The infected person with the virus is likely the index case that spread the virus to others locally.
Dacuma pointed out that the index case(s), especially those that did not cause local transmission, does not form part of the epidemic wave.
"When the virus is transmitted locally to other people, there is an incubation period. For COVID-19, the incubation period (meaning the virus infecting the new host but without any symptoms/clinical signs yet) can be on average 5.2 days up to 14 days. That is why you see a flat line after the introduction of the index case," she explained.
"After the incubation period, newly infected hosts develop symptoms and clinical signs – that is why they seek medical attention. In addition, because of the threat of the pandemic, our country increased its vigilance and capacity to screen more people," she added. Hence, the rapid spread and increase of cases.
Dacuma attributed the ease of movement of people by plane, land transportation, or boat that made it very easy to spread the virus across the Philippines. "Hence, we have an epidemic meaning it has spread all over to many provinces and infecting thousands of people."
"We will know that we have reached the peak of the curve when the net increase in the number of active cases is starting to decline because of lockdowns and country-wide vigilance, among others," she said.
"Eventually, there will be reduction in number of cases where the number of infected people recovering will be higher than those becoming infected. Then there will be a point where there are no more cases. That’s when we know the epidemic has stopped," she added.
People stand on designated spots to maintain social distancing at a market during a government-imposed enhanced quarantine as a preventive measure against the COVID-19 novel coronavirus in Manila on April 21, 2020. (Photo by Maria TAN / AFP / MANILA BULLETIN)
She noted that the COVID-19 epidemic in the Philippines most likely started with an imported case from an infected person or persons who entered the Philippines.
The infected person with the virus is likely the index case that spread the virus to others locally.
Dacuma pointed out that the index case(s), especially those that did not cause local transmission, does not form part of the epidemic wave.
"When the virus is transmitted locally to other people, there is an incubation period. For COVID-19, the incubation period (meaning the virus infecting the new host but without any symptoms/clinical signs yet) can be on average 5.2 days up to 14 days. That is why you see a flat line after the introduction of the index case," she explained.
"After the incubation period, newly infected hosts develop symptoms and clinical signs – that is why they seek medical attention. In addition, because of the threat of the pandemic, our country increased its vigilance and capacity to screen more people," she added. Hence, the rapid spread and increase of cases.
Dacuma attributed the ease of movement of people by plane, land transportation, or boat that made it very easy to spread the virus across the Philippines. "Hence, we have an epidemic meaning it has spread all over to many provinces and infecting thousands of people."
"We will know that we have reached the peak of the curve when the net increase in the number of active cases is starting to decline because of lockdowns and country-wide vigilance, among others," she said.
"Eventually, there will be reduction in number of cases where the number of infected people recovering will be higher than those becoming infected. Then there will be a point where there are no more cases. That’s when we know the epidemic has stopped," she added.