95% COVID-19 patients asymptomatic: Study

By Abdul Qadir Qureshi
(Pakistan News & Features Services)

More than 9 out of 10 people infected with coronavirus (COVID-19) experience have had no symptoms of the disease, a new study, carried out by the Aga Khan University (AKU) researchers, revealed.

Karachi has the most COVID-19 cases in Pakistan and the study saw AKU faculty investigate COVID-19’s prevalence in parts of the city with high and low rates of transmission in the community in April and June 2020. 

They found out that 95 percent 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 of the illness such as a cough, fever or sore throat. In other words, they were asymptomatic. 

The proportion of asymptomatic cases in Pakistan is much higher than 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 strain as in Spain and the UK, according to researchers. 

The results also indicated that children and adolescents are just as likely to catch the disease as adults. Men and women face the same risk of being infected. 

The study also confirmed a sharp rise in COVID-19 cases between April and June this year from 0.2 per cent to 8.7 per cent in low community transmission areas such as Ibrahim Hyderi, and from 0.4 per cent to 15.1 percent in high community transmission sites like Safoora Goth, Faisal Cantonment, Pehlwan Goth and Dalmia/Shanti Nagar.

These results were in line with the federal government’s national seroprevalence study where antibody testing found that overall, 11 percent of Pakistanis had contracted the disease.

“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,” Dr Imran Nisar, an assistant professor at AKU and co-investigator on the study, remarked.

Over 2,000 participants were engaged in the first two phases of the study. The researchers are currently undertaking a third serosurvey and plan to do a fourth in September 2020. These surveys will show the impact of easing lockdowns around Eid-ul-Azha and the impact of the 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. 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,” Dr Fyezah Jehan, an associate professor at AKU and co-investigator on the study, explained.

AKU’s Dr Nadia Ansari and Dr Mashal Amin as well as US-based international collaborators Dr Bailey Fosdick and Dr Daniel Barremore also contributed to the study.