The test positivity rate (TPR) in Ghaziabad has been on the decline over the past month, ever since the district ramped up rapid antigen testing that had started on June 26. While officials said various measures have helped bring about the decline, it was too early to assume that the disease is on its way out.
Ghaziabad saw a major spike in the number of cases in the months of June and July. As of May 31, there were only 305 cases, which climbed to 4,321 as on Thursday. The spike was primarily attributed to the relaxation of in lockdown norms starting June 8.
According to the weekly figures from the health department, the TPR was 9.19% in the week from May 31 to June 6 with positive cases during the period at 155. This climbed to 15.33% during the week from June 21 to June 27.
In the week from July 19 to July 22, the TPR dropped to 3.22%. However, since June 26, antigen tests have become the primary testing regime in the district, constituting 54% (40,500 as on Thursday) of all tests done to determine Covid-19.
Antigen tests are inherently unreliable with very poor sensitivity, which means that its ability to detect true positives is low and could result in many negative tests turning positive under an RT-PCR test.
{{/usCountry}}Antigen tests are inherently unreliable with very poor sensitivity, which means that its ability to detect true positives is low and could result in many negative tests turning positive under an RT-PCR test.
{{/usCountry}}“What we have observed in Ghaziabad is that testing during initial months was done for selective groups. Now, with arrival of rapid kits, the net is wider. So, the sampling/testing rate has gone high and positivity rate is less. The RT-PCR test has about 70% sensitivity while rapid antigen kits have sensitivity of about 60%. So, there is not a major difference and the samples turning negative through rapid kits are anyway test through RT-PCR for finding true negative. So, the major reason for less positivity is more linked to widespread testing being done now,” said Dr VB Jindal, president of Indian Medical Association, Ghaziabad.
Despite this, its share is high because of two advantages: point of care testing and no need of taking it to a laboratory, and that it gives a result within 30 minutes, as compared to the two days it would take an RT-PCR test.
“The weekly trend shows that positivity is on decline but we cannot assume that the effect of Covid-19 is on decline overall. We will have to observe the trend for about 1-2 months before we can say that there is an assured declining trend. On the other hand, we have taken various measures to bring down the case positivity,” said Ajay Shankar Pandey, district magistrate.
“Initially we put up restrictions at the Delhi-UP border in order to prevent cross-border infection. Then, we took up rigourous containment exercise in various areas and presently it is being taken up in 21 different localities which have 10 or more active cases. The weekend restrictions directed by the state government have also helped as we taken up cleanliness and sanitization for two days to curb spread of infection.”
“We are analysing the week wise declining trend of positivity in the district. One of the major factors behind the reduced TPR is the test sensitivity. With the rapid antigen kits, we have positivity of about 3-4% while the positivity with RT-PCR tests is about 6-7%. So, this could be a reason why the trend is on decline while more tests are getting done through rapid kits nowadays,” said an officer from the district health department who wished not to be named.
The RT-PCR tests are considered as more sensitive than the rapid kits as they have a higher rate of detection and can even detect minutest traces of virus including the traces of dead virus.
Officials said that fatality rate has also come down. In June alone, the district had suffered 51 of the 64 deaths since the outbreak of the disease in March.
According to official records, the fatality rate was 4.1% in the month of June with 51 deaths and 1,243 monthly cases. From July 1 to 11 the rate came down to 0.5% with seven deaths out of 1,544 cases during the period. The officials added that the rate has further come down to 0.2% with just two deaths out of 977 cases during the period.
“To keep check on rising number of deaths we streamlined our systems and working round the clock on early detection, testing and speedy referral to prevent any patient getting into serious condition. Our focus is on every individual patient in order to further lower the death rate,” Pandey added.
Box:
Samples/test +ve cases positivity
May 31 to June 06 1686 155 9.19%
June 7 to June 13 1845 162 8.78%
June 14 to June 20 2258 249 11.03%
June 21 to June 27 3398 521 15.33%
June 28 to July 4 13183 698 5.29%
July 05 to July 11 17178 948 5.52%
July 12 to July 18 17918 935 5.22%
July 19 to July 22 10521 339 3.22%