ISLAMABAD: A survey has suggested that around 300,000 persons have been infected with the novel coronavirus in Islamabad after which the city may be inching towards achieving “herd immunity”.

The study has also shown that a vast majority of the individuals exposed to the virus are asymptomatic, that is they are generally not showing symptoms of Covid-19 even after being infected with the dreaded virus.

During the last 24 hours, 2,276 new infections were detected, which took the country’s total caseload to 259,401. During the period, 48 people died from the virus, taking the death toll to 5,465. So far 178,737 people have recovered from the disease.

The National Command and Operation Centre (NCOC), meanwhile, decided to use digital algorithms in 10 cities to determine how many people were following the standard operating procedures (SOPs) formulated to slow down the spread of the disease.

The study — titled “Sero-Epidemio-logical Survey for Covid-19” — was carried out between June 1 and June 25 in the geographical limits of the Islamabad Capital Territory (ICT).

Most of the infected people are asymptomatic, says NIH chief

The executive director of the National Institute of Health (NIH), Maj Gen Prof Dr Aamer Ikram, told Dawn that during the study equal representation from the rural and urban areas was ensured.

According to the Pakistan Bureau of Statistics, ICT is divided into 44 administrative units: 12 of them urban and 32 rural. As per the national census of 2017-18, the population of the city is 2,006,572 (urban 1,014,825, 50.6 per cent; and rural 991,747, 49.4pc).

Dr Ikram said that after applying the standard techniques sample size required was found to be 4,328 for the survey. “A structured, pre-tested questionnaire was used to gather data relating to demography, clinical issues and exposure and risk factors from the community. Blood samples were collected from participants who were tested for immunoglobulins against Covid-19…. Throat or nasopharyngeal swabs were also collected from those having symptoms or a contact history with a positive case for PCR testing. All samples were tested at the virology lab of NIH,” he said.

A preliminary analysis showed a prevalence of 14.5 per 100 population for Covid-19, he said. “As for area-wise distribution of the disease, rural union councils were more affected. Out of all the union councils, Chattar was found to be the most affected, followed by the union councils of Muhrian and Tarlai Khurd.

“Considering the ages, the most affected group comprised people of between 41 and 50 years, followed by the 31-40 years group and 51-60 years group. PCR positivity rate was found to be 17pc,” he said.

“The calculated prevalence for Covid-19 in ICT is 14.5pc which translates into 290,000 individuals, who have been exposed to the SARS-CoV-2 virus and have developed immunoglobulins against the virus. This should be seen in the context that a vast majority of the individuals exposed to the virus are asymptomatic.”

In response to a question, Dr Ikram said the objective of the survey was to reveal the number of people who have already been exposed to the virus.

According to an official statement, an enhanced surveillance strategy that focuses on population-based methods is mandatory to understand the actual situation on the ground and then successfully control the pandemic.

“Asymptomatic/mild cases of Covid-19 are usually not picked up on routine surveillance and hinder estimation of the true population infection rate. Therefore, estimation of true population infection rate is mandatory to effectively guide public health interventions. To address the needs, following the WHO guidelines, a population-based, age-stratified, sero-epidemiological survey was conducted in Islamabad to determine the extent of infection among the population, age-specific attack rates and the fraction of asymptomatic or subclinical infections,” the statement said.

Dr Ikram said that as about 15pc of the population had developed antibodies for Covid-19, it could be said that about 300,000 people in the federal capital had been infected with the virus. “If 50pc of the population would be infected, the concept of herd immunity would kick in. Now we will hold similar studies in other cities,” he said.

Digital algorithms

The NCOC on Thursday decided to use digital algorithms in 10 cities to determine the number of people who have been following the SOPs.

Minister for Planning, Development and Special Initiatives Asad Umar said there were two major SOPs for Covid-19 — wearing face masks and maintaining social distancing.

“We have deployed teams to observe the implementation of SOPs in markers, mosques, offices, etc and to file reports. However it is observed that perceptions of team members can vary from one to another. So it has been decided that in the 10 cities digital algorithms would be used to check the implementation of SOPs,” he said.

When asked how the data would be collected, Mr Umar said that appropriate figures would be collected from CCTV footage and footage run by news channels.

“During the meeting on Thursday it was suggested that technology could be used to reveal data with an accuracy of 92pc. The new technology has been tested and now it will be implemented in 10 cities, including the federal and provincial capitals,” he said.

Data from the NCOC showed that on an average 23,403 tests were conducted between June 1 and June 15, with the per day infections detected coming to 5,056. However from July 1 to July 15, 22,969 tests were carried out each day and the average infections detected stood at 3,097.

Published in Dawn, July 17th, 2020