ISLAMABAD: Pakistan reported the highest number of cases over the past around 80 days, with the positivity ratio in Karachi and Hyderabad surpassing 10 per cent.

National Command and Operation Centre (NCOC) member Dr Shahzad Ali Khan said the rising number of cases showed that effectiveness of the vaccine was reducing because of the time lapse and suggested that people go for the booster shots.

He said possible reasons for the upsurge are waning of vaccine immunity after six months, avoiding booster doses, virus mutations into more virulent type causing higher infectivity, going back to almost normal lifestyle in crowded places in Karachi, Hyderabad and Islamabad, increasing international and local travelling, less care by people about social distancing and masks, and seasonal pattern like flu as Covid-19 belongs to the same flu family.

According to NCOC data, 171 cases of Covid-19 were reported from across the country on Monday and the positivity rate was 1.53pc. Fifty-seven patients were on critical care. The country reported 238 cases on April 8.

According to the data, the positivity ratio was 16.67pc in Hyderabad and 10.08pc in Karachi on Monday. Mirpur reported over 5.26pc positivity, while the cities recorded over 2pc included Islamabad, Muzaffarabad and Mardan.

The data showed that 259,286,753 doses of vaccine have been administered so far. As many as 124,721,404 people have become fully vaccinated and 15,825,367 got booster doses.

Dr Shahzad Khan said the increase in the number of cases was a proof that effectiveness of the vaccine was decreasing due to time lapse.

“Vaccine boosts immune system, but with the passage of time its effectiveness reduces and that is why it has been suggested that the masses should be administered booster dose,” he said.

He said continuous mutations in Coronavirus, which is a ribonucleic acid virus, had been observed. “Moreover, the whole country has been opened and restrictions on businesses and tourism have been lifted. I believe this has also increased the spread of the virus. People should strictly adhere to the standard operating procedures, wear masks and get them vaccinated,” said Dr Khan, who is also Vice Chancellor of Health Services Academy.

“Moreover, there is also a possibility that the virus has further mutated just like a variant Omicron’s transmissibility was very high but it was less virulent. Even if virus has been mutated, there is a need to get booster dose of the vaccine as it will increase the immunity level,” he said.