States asked to step up testing
NEW DELHI: The Union health ministry on Sunday directed all states that have seen a resurgence of new Covid-19 infections to again step up vigilance against the disease by scaling up testing, using more gold-standard RT-PCR tests, reinforcing strict containment strategies and closely monitoring for mutant strains.
The direction comes at a time when states such as Maharashtra have seen a clear second wave of infections rising over the past fortnight, forcing the reintroduction of social curbs such
as lockdowns amid fears of mutant strains gaining ground. The states have also been asked to focus on better clinical management of patients in districts reporting high deaths.
Other than Maharashtra, regions such as Punjab, Haryana and Jammu & Kashmir, Chhattisgarh and Madhya Pradesh are all experiencing what appears to be the start of a second Covid wave. The first wave, meanwhile, continues unabated in Kerala.
Maharashtra and Kerala, by themselves, have been responsible for more than 75% of all new cases reported in the country in the past week. Pushed by these two, the seven-day average of daily cases across the country, which dropped to 10,988 for the week ending February 11, has again started rising — it stands at 12,387 in the past week.
In light of this resurgence, states have been directed not only to increase the number of tests but also raise the proportion of the more reliable RT-PCR tests. In fact, the states have been told to verify all the negative rapid antigen tests using an RT-PCR test. “All negative rapid antigen test results to be mandatorily followed by RT-PCR test and no such negative persons are to be missed,” the ministry said in a release.
RT-PCR is a molecular test that works by amplifying the genetic material of the Sarscov-2 virus that causes Covid-19 to detect it in a patient’s swab samples. The rapid antigen tests on the other hand works by detecting broken-down proteins present on a nasal swab sample. The latter, therefore, can miss the virus if it is present in trace amounts or if the swab missed the virus during sampling. In other words, if a person tests positive in a rapid antigen test, they certainly have the infection, but the test can miss as much as 50% of positive cases by throwing up false negatives.
The states have also been asked to focus on genomic sequencing to detect any mutant strains.
With worries of the UK variant of the Sars-cov-2 virus coming to India – and now the Brazilian and South African variant – the government set up a genomic sequencing consortium to sequence up to 5% of the total positive samples in the country to detect new imported as well as indigenous variants.
With over 10 million cases of Covid-19 in India, experts believe that new variants of Sars-cov-2 may emerge in the country due to selection pressure which is put on the virus with so many individuals being already infected.
“For a new variant to emerge two things are needed – one, mutations that happen naturally as errors are made when the viral genome is being replicated; two, the mutations offering a selective advantage to the virus such as higher transmission, better binding to the receptor, or evading an existing immune response. So, as more and more people get infected and develop immunity to the virus, its virulence (severity of disease) will likely go down but it will increase the selective pressure on the virus to mutate,” said Dr Shahid Jameel, director of Trivedi School of Biosciences at Ashoka University and former CEO of Wellcome Trust/dbt India Alliance in a webinar earlier this week.
In Maharashtra, the state that saw the highest increase, the weekly positivity rate – proportion of samples that return positive among the total tested – also went up from 4.7% to 8%.
Experts believe the spread of the infection to be under control when a positivity rate of 5% or less is maintained over two weeks. There are five states and union territories in the country that have a positivity rate higher than the national average of 1.79%.
Topping the list is Maharashtra with 8.1%, followed by Kerala with 7.9%, then Andhra Pradesh with 3.3%, Goa with 3%, and Chandigarh with 1.8%.
The highest increase in the weekly number of cases was noted in Akola (55%), Yavatmal (48%), and Amravati (47%), according to data shared by the Union health ministry. On Sunday, the Maharashtra government announced week-long hard lockdown in state’s Amravati district from Monday in order to contain the rising infections. In Pune, the district administration announced the closure of all schools and coaching institutions on Sunday.
An increase of 19% in the weekly number of cases was also seen in the Mumbai Suburban area.
“There is a need to study the new infections that are being reported from Maharashtra, where a high proportion of people are likely to have been exposed already. We need to see whether the infections are happening in people who haven’t had it earlier or are these re-infections. Everyone should be asked about their history of the infection,” said Dr T Jacob John, former head of the department of virology at Christian Medical College-vellore.