Covid-19 positivity rate in Delhi above 5%: Why it's a matter of concern?

The WHO has said that the 5% mark is ideal for an outbreak to be considered as under control. The Delhi government has taken a number of steps to check the spread of Covid-19.

The Delhi government on Tuesday announced night curfew, which will be in place from 10pm to 5am, to check the spread of the coronavirus disease (Covid-19) in the national capital. The decision has been taken after continuous rise in the number of cases over the past few weeks.

Passengers stand in a queue to register for a RT-PCR test at a bus stand in New Delhi on Tuesday. (AFP Photo)

But what has been equally worrying for the government is that the positivity rate - a measure of the number of positive cases from those tested - crossed the five per cent mark. This is the threshold that the World Health Organization (WHO) identifies as ideal for an outbreak to be considered as under control.

With 3,548 cases after 64,003 tests, Delhi's positivity rate jumped to 5.54% on Monday, which is the highest since December 2 last year.

Why is this a matter of concern?

The positivity rate determines the spread of the infection, and when it goes above the five per cent threshold, experts sound an alarm saying the disease in on its way to become unmanageable.

And doctors agree with that. “We have to keep a close eye on the numbers. The increasing positivity rate indicates that the disease is spreading faster," Dr Jugal Kishore, head of the department of community medicine at Delhi's Safdarjung hospital, said when the fresh spike just began in the national capital in March.

“There is a laxity in the Covid-19 norms in Delhi now... This needs to change,” he added.

How has Delhi fared in terms of positivity rate?

On March 15, 368 cases were reported in Delhi, which showed a positivity rate of 0.6%. This is when Delhi health minister Satyendra Jain said the national capital is at a benchmark of Covid-19 cases. "In Maharashtra, the positivity rate is 16 per cent, Gujarat's positivity rate is three times of Delhi. The positivity rate has reached six times in Punjab, seven times in Kerala and 30 times in Maharashtra," Jain said on March 15.

Since then, the rate has been on an upward trajectory. In week starting March 22, new cases grew to 888 while the positivity rate inched up to 1.3%.

On March 29, the day of Holi, the positivity rate rose to 2.7%. That day, 1,904 cases were recorded.

In the week since Holi, the positivity rate rose exactly by double to reach 5.5%.

What the Delhi government is doing?

"The case positivity rate was 4.64 per cent on Sunday. Random tests are being done at a fast pace and capacity is being ramped up. More than 80,000 tests are being conducted a day which is five times more than the national average," Delhi health minister Satyendra Jain told reporters on Monday.

The Kejriwal government is taking a number of other decisions to contain the contagion, the minister said, adding that micro-containment zones are being created wherever two to three Covid-19 cases are detected.

What are the positivity rates in other states?

In Maharashtra, the worst-hit state, the positivity rate stands at 14.6 per cent. Out of the 2,07,15,793 laboratory samples, which were taken until today, 30,57,885 have tested positive for Covid-19, the state government's health department showed.

Punjab, another badly affected state, has seen its positivity rate grow at a fast pace. According to Punjab health minister Balbir Singh Sidhu, a positivity rate of 2.9% was recorded from February 27 to March 5, which increased to 7.9% between March 27 to April 2.

In Chhattisgarh, among the states where the Centre has sent its teams to help tackle the spread of the disease, the positivity rate stands at 20%., Union health minister Harsh Vardhan said on Tuesday. The state's health minister TS Singh Deo said on Saturday that the positivity rate is not as high as compared to September last year. "In September, the maximum daily cases recorded was 3,900 from about 27,000 tests. The present number of daily cases on Thursday is from 40,000 tests. So the positivity per cent is less as compared to that in September," Deo told news agency ANI.