NEW DELHI: A mutated strain of SARS-CoV-2, originated in Spanish farm workers, is suspected to be behind the second wave of covid-19 infections in Europe. A study done by University of Basel, Switzerland, and University of Valencia in Spain and published in a scientific journal, that is yet to be peer reviewed, has found that a variant of SARS-CoV-2 emerged in early summer of 2020, presumably in Spain, and has since spread to multiple European countries.
First observed in Spain in June, the mutation has been at frequencies above 40% since July. Outside of Spain, the frequency of this variant has increased from very low values prior to 15 July to 40-70% in Switzerland, Ireland, and the UK in September. It is also prevalent in Norway, Latvia, the Netherlands, and France, the study said.
Scientists have said that this variant rose in frequency in multiple countries and have indicated that the rise in frequency could also be due to epidemiological factors. The scientists have said travel may also be a reason for the spread. “The cluster we describe here – 20A.EU1– was dispersed across Europe by travelers to and from Spain and repeated imports might be sufficient to explain the rapid rise in frequency and the displacement of other variants,” the author said in the study.
“On the other hand, we observe a consistent and rapid growth of this variant in multiple countries and its frequency is above 50% in some localities. In countries where more than one introduction (of returning tourists) has occurred, it appears that multiple introductions have expanded. Its frequency in the UK has continued to increase even after quarantine-free travel was discontinued and the main summer travel period ended,” the study said.
However, this acceleration of transmission also coincided with the arrival of fall and seasonal factors are an alternative or compounding explanation. The strain’s observed introduction and rise in prevalence in multiple countries, the scientists in the study said, implies that the summer travel guidelines and restrictions were generally not sufficient to prevent onward transmission of introductions.
“While long-term travel restrictions and border closures are not tenable or desirable, identifying better ways to reduce the risk of introducing variants, and ensuring that those which are introduced do not go on to spread widely, will help countries maintain often hard-won low levels of SARS-CoV-2 transmission,” the study said.
The study comes at a time when India has opened up its economy under Unlock 5 and lifted all travel restrictions across states. This is also the festival season for the country and the approach of the winter season.
The Indian Council of Medical Research (ICMR) is tracking transmission in the country for mutations. Union health minister Harsh Vardhan recently said government scientists have not found any significant mutation in the virus circulating in India.
Public health experts, however, have warned that India needs to be cautious.
“At a time when covid-19 positive cases are rising in some parts of the country and people are not following public health safety guidelines diligently, even mutated versions of the virus can become the cause of a large number of infections. We must be very careful during the upcoming festivals and adhere to public health and safety guidelines by all means,” said Dr Gyan Bharti, Pulmonologist at Columbia Asia Hospital, Ghaziabad, Uttar Pradesh.