95% of those with COVID-19 in Karachi show no symptoms, reveals study

KARACHI: A new study by Aga Khan University (AKU) researchers reveals that 9 out of 10 people infected with coronavirus in Karachi experience no symptoms of the disease although the metropolis has been reporting the most COVID-19 cases in the past.

The study – which was conducted by AKU faculty to investigate COVID-19’s prevalence in parts of the city with high and low rates of transmission in the community during April and June 2020 – highlighted that 95% of those who tested positive for COVID-19 through blood tests, which register the presence of antibodies to fight the disease, reported feeling no symptoms such as a cough, fever or sore throat. In other words, they were asymptomatic.

The research report, prepared in collaboration with US-based international collaborators Dr Bailey Fosdick and Dr Daniel Barremore, noted that “the proportion of asymptomatic cases in Pakistan is much higher than in the developed world”.

Since asymptomatic people do not seek hospital treatment this may help explain why Pakistan’s hospitals have not been under the same burden as in other developed countries of the world like Spain and the UK.

In addition, the study also suggested that children and adolescents are just as likely to contract the virus as adults, and men and women face the same perils of being infected from the contagious disease.

Read more: District Central most affected by coronavirus in Karachi: report

Confirming a sharp rise in COVID-19 cases between April and June this year, the study unveils that the results are in line with the federal government’s national seroprevalence study where antibody testing found that overall 11% of Pakistanis had contracted the disease.

An assistant professor at AKU and co-investigator on the study, Dr Imran Nisar, said: “The sharp increase in antibody levels in an area with low reported cases indicates that the virus continues to spread unchecked in populations where testing rates are sub-optimal."

Over 2,000 participants participated in the first two phases of the study where researchers are currently undertaking a third serosurvey and plan to do a fourth in September 2020.

These surveys will also reflect on the overall impact of easing lockdowns around Eidul Adha and during Muharram processions on the coronavirus transmission rate in communities.

"Antibody testing or seroprevalence provides a true picture of the burden of COVID-19 as they capture asymptomatic cases who represent silent carriers of the disease," said Dr Fyezah Jehan, an associate professor at AKU and co-investigator on the study.

"Understanding how, when, and in what types of settings, COVID-19 spreads is critical to developing effective public health and infection prevention measures to break chains of transmission."