Number of cases increasing in Gurugram due to more testing, say officials

The number of Covid-19 cases in Gurugram doubled in the last week, with addition of at least 71 cases between May 1 and May 8. The district at present has a total to 142 cases.

Between May 1 and May 8, Gurugram’s doubling time decreased from 36 days to around 7 days, according to government data.

The doubling rate of an infectious disease is a temporal indicator. It estimates the number of days that it will take for the total number of cases to double. The lesser the number of days it takes for cases to double, the higher the doubling rate.

In Haryana, the cumulative number of Covid-19 cases is doubling every eight days — as opposed to every 24 days, which was the rate two weeks ago. Health officials say that this acceleration is due to an increase in targeted sampling and RT-PCR testing of both symptomatic and asymptomatic patients.

Officials also said that, given the surge in Haryana and in Gurugram, and to check the spillover of infection from adjoining Delhi and Punjab, testing numbers are only going to be ramped up in coming days.

Data shows that the growth rate of Covid-19 cases in Gurugram was slow till April 30.

Till March 31, cumulative Covid-19 cases in Gurugram were 24. It increased to 46 on April 8. No new case was reported for the next 10 days. The number gradually increased to 61 on April 24 and further to 71 on May 1.

“The growth rate was slow, so the cases were multiplying after every 36 days. In last one week, cases have suddenly increased from 71 to 140. It is the highest spike so far, bringing down the doubling rate to 7.2 days,” said Ashok Meena, officer in-charge for state’s Covid-19 data, and CEO of Ayushman Bharat and commissioner Food and Drugs department.

Gurugram was one of the first districts in Haryana to report a case of the virus. On March 4, a Paytm employee had tested positive for Covid-19. Cases that were reported thereafter, were largely traced back to overseas travels or people having come in contact with Tablighi Jamaat attendees. Data shows Covid-19 cases were multiplying in 18 days at that time.

Meena said, “To calculate the doubling rate we take seven days average. It includes a mathematical calculation called Cumulative Annual Growth Rate (CAGR), where we take average of Covid-19 cases reported in the last seven days. It can be calculated every day, also every three days or five days. But it is the Central government’s mandate to calculate the doubling rate after every seven days. It is a dynamic process and therefore the rate changes every week.”

Dr Rajesh Kumar, epidemiologist and former professor at the department of community medicine, PGIMS Chandigarh, explained that the doubling rate is related to the disease’s basic reproduction number, or R0. “For Covid-19, the basic reproduction number is supposed to be something between 1.5 to 3.5, meaning that one infected person will infect between 1.5 to 3.5 others. If the doubling rate is accelerating, it means that public health interventions have not reigned in the spread of the virus. The R0 may not be decreasing,” Kumar said. For India, the R0 value as calculated on May 9 was 1.27.

STATE’S DOUBLING RATE

Government data shows that in Haryana, till April 17 the doubling time was 24 days. From 275 cases in the third week of April, the count of persons infected with Covid-19 reached 357 on May 1, bringing down the doubling time to 18 days.

The largest spike in Covid-19 cases was noticed between May 1 till May 8. From 357 cases,the number of positives count shot up to 647.

“This sudden spurt in the number of cases further reduced the doubling time to eight days. Cases were being reported from districts like Jhajjar, Sonepat and Panipat, which barely had any cases earlier,” said Meena.

He added, “Most of these cases have links with Delhi and other districts. It includes vegetable sellers who had links with Delhi’s Azadpur mandi, police personnel, health workers and Nanded pilgrims from Punjab. Therefore, to break the chain of transmission we are testing both symptomatic and asymptomatic cases now, which is why the numbers are increasing,” said Meena.

A senior official in Haryana’s Integrated Diseases Surveillance Program, requesting anonymity said, “The accelerating rate could also mean that presymptomatic cases, which were going undetected earlier, are now showing signs of illness,” the official said.

According to experts, it is a step in the right direction when it takes more days for the number of cases to double (if combined with an increase in testing numbers, and widening of testing criteria).

However, if the window becomes shorter, it could mean that transmission was still happening. However, the senior IDSP official said that Haryana’s increasing doubling rate is merely a result of more targeted testing. “Our surveillance is becoming more efficient at finding and testing the right people, so naturally the cases will go up, and impact the doubling rate,” they said.

The official also said that, just like Punjab, Haryana too was responding to the recent spike in cases by ramping up testing numbers. “If there is a surge in cases, it means that we need to keep increasing the number of tests until the daily percentage of positives starts to decline once again. Until then, we cannot be lax on testing.”

Weekly data, however, shows that numbers have not significantly been ramped up. Between April 17 and April 23, Gurugram tested 1,525 samples. The following week (between April 24 and April 30), the district tested 1,719 samples, a slight increase. Between May 1 and May 7, the testing numbers recorded a decline, with just 1,487 samples tested.

However, in the last two days, Gurugram had tested 558 samples, with the numbers expected to increase in the next five days, officials said.