As fest season approaches, test positivity rate begins to inch up
MUMBAI: Maharashtra’s weekly positivity rate has increased marginally from 2.48% to 2.6% in the week between August 25 to September 1 compared to the week between August 18 and 24. Public health experts attribute to the rise in Covid-19 cases due to the lockdown relaxations starting the second week of August; districts such as Mumbai, Thane and Pune have recorded the highest rise.
However, though the uptick is slight, it is still a matter of concern. Here’s why: the test positivity rate (TPR) has increased despite a decrease in testing. TPR is a function of the number of cases to every 100 tests conducted. If the disease spread was in check, a decrease in the number of tests would be accompanied by a corresponding decrease in the number of Covid cases.
Data provided by the state health department shows that 1,327,214 cumulative tests took place between August 18 and 24 of which 32,994 samples tested positive for Covid-19. In the following week, the number of tests between August 25 and September 1 dropped to 1,288,798, but the number of positive cases increased to 33,751.
Weekly tests in Mumbai dropped from 273,794 (conducted in the week between August 18 and 24) to 264,731 in the week between August 25 and September 1. But the weekly positivity rate increased from 0.9% to 1.1%.
Similarly, in Thane weekly testing dropped by 10.8% from 128,321 to 114,454 in the same two weeks. However, the positivity rate increased from 1.3% to 1.7%. A high TPR accompanied by decrease in testing indicates that the spread of the disease is still prevalent and is not under control. Lesser testing means that people who are being infected may be passing it on to others without realizing.
Significance of testing
Let’s take the case of Pune where the daily cases are rising. Together with Ahmednagar, Satara and Sangli, these districts have been recording some of the highest positivity rates in the state during the second wave. This continues to be the case: of the 44,366 patients registered during August 22-31, 70% are from these four districts. However, though the latter three have been registering a gradual dip in daily case numbers, the weekly positivity rate of Pune has surged to 6.3% in the last seven days from 5.6% that was recorded between August 18 and 24.
However, in Pune, the number of tests has actually gone up.
Pune conducted 113,026 tests between August 18 and 24, which increased to 115,914 in the last seven days.
“With the identification of the Delta Plus variants in the district, we have increased the daily testing which has also contributed to the rise in weekly positivity rate,” a senior health officer from Pune health department said.
A total of 127 Delta Plus variants have been recorded in the state – six in Pune.
Increased testing – alongside other measures like contact tracing, mask wearing, physical distancing and ensuring effective ventilation – helps in controlling the spread of a pandemic. In the case of Pune’s numbers, the rise in cases is an indication of high prevalence; it’s also an indication that the spread isn’t going unchecked.
Next 15 days crucial
The roll out of relaxations from Covid-19 lockdown in the state is one of the factors responsible for the rise in numbers. Starting August 15, public places like shops, malls, and restaurants were allowed to operate till 10pm, while private offices were permitted to operate all days of the week with staggered shifts. Restaurants, gymnasiums and spas were allowed to operate at 50% capacity. The number of people allowed to attend wedding ceremonies was increased to 200 in open venues. Indoor games were allowed till 10pm to those who were fully vaccinated.
The public health department is anticipating a rise in cases in two weeks after the commencement of the Ganesh festival on September 10. The department has cited the example of Kerala, which saw a rise in cases immediately after Onam.
“Till now, the situation is under control. With festivals around the corner and the presence of Delta variants in the crowd, people need to follow Covid-19 appropriate behaviour. The next 15 days will be essential to understand the pattern of the pandemic. Meanwhile, the state government is focusing on boosting the vaccination drive across the state,” said Dr Rahul Pandit, member of the state Covid-19 task force.
Mumbai and Thane officials said that the slight uptick in positivity rates is something to keep a close eye on.
“The slight rise in cases is expected post relaxation of the restrictions. Also, local train services have also partially resumed. But so far, we haven’t recorded any sudden surge in cases. Now, we have zero containment zones in slums,” Suresh Kakani, additional commissioner, Brihanmumbai Municipal Corporation (BMC), said.