About 22 million people in Britain are living in zero-COVID areas, according to the latest figures.
Data reveals that the latest lockdown, together with the vaccination rollout, have successfully reduced cases and, as a result, deaths.
The areas, which include much of the Scottish Highlands a large chunk of western England, and most of Devon, did not report any deaths due to coronavirus in April, according to BBC News analysis.
And Plymouth in Devon, home to more than a quarter-of-a-million people, has not reported a COVID death in the last 57 days. Oxford, and Maidstone in Kent, have gone 60 days without a COVID-related death.
However, the 19 worst-hit councils accounted for more than a third of the deaths occurring in April.
The areas with the highest death rates include Mid and East Antrim, and Antrim and Newtownabbey, both in Northern Ireland, as well as Sedgemoor in Somerset and Bradford, West Yorkshire.
Scientists advising the government believe that the focus in the coming months will turn to identifying and containing local and regional outbreaks.
Areas that are reporting more deaths reported more cases during February and March, thought to be fuelled by more transmissible variants of the virus.
Professor Christina Pagel, a member of the unofficial coronavirus advisory body Independent SAGE and director of the Clinical Operational Research Unit at University College London, has warned that the highly transmissible Indian variant could threaten the UK's recovery from the pandemic if border controls are not tightened.
Writing on Twitter she said: "What we are seeing in the UK could just reflect the situation in India as people travelled here (likely), or reflect similar variant behaviour in the community here.
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"Border measures in UK are pretty woeful - see evidence given to the parliamentary all party group last week from UK border control... Negative tests on departure cannot be verified, no data on adherence to quarantine, very few checks.
"Last week, 47 plane passengers from Delhi to Hong Kong tested positive for covid - 22 of whom only tested positive right at end of isolation period (presumably infected on journey). Are we so sure we would spot these using our system?"
Prof Pagel urged the government to tighten border controls, and step up testing and tracing in the UK in order to identify anyone carrying the Indian variant.
So far two new variants linked to the one first found in India have been identified in England.
Public Health England (PHE) said the two variants share the same lineage – a distinct fingerprint of genetic mutations – as the Indian variant known as B.1.617.
We can't assume we have spotted all cases in UK. We must aggressively trace contacts, surge test, improve border processes.
Regardless of situation here, things are worsening in India. If you feel able, please consider donating to relief efforts /END
— Prof. Christina Pagel (@chrischirp) April 29, 2021
The two variants are designated as “variants under investigation” (VUI) – the same as B.1.617 – rather than “variants of concern” (VOC), such as those first identified in Kent, Manaus (Brazil) and South Africa.
PHE said it has identified 202 cases of one of the variants and five cases of the other that are “geographically dispersed in England”.
It said there is no evidence that these variants cause more severe disease or make the current vaccines any less effective.
India was placed on England’s travel “red list” from 23 April, restricting arrivals to citizens and residents who must quarantine in a hotel.
The country has been plunged into a healthcare crisis due to a surge in cases that may in part be due to the variant.
An extra 61 confirmed cases of B1617 were recorded in the UK in the week up to 28 April, bringing the total to 193 cases, PHE data shows.
PHE said it has been monitoring the variants since March and has increased lab testing “to better understand the impact of the mutations on the behaviour of the virus”.
There are a total of 226,635 cases of the Kent variant, known as B.1.1.7, in the UK, PHE figures show.
There are four variants of concern and nine variants under investigation which have been identified in the UK.
At a Downing Street press conference on Wednesday, health secretary Matt Hancock said concern around the impact new variants could have on the UK vaccine programme was behind the policy decisions on tight border controls.
Professor Jonathan Van-Tam, deputy chief medical officer for England, said it was difficult to assess how new coronavirus variants would impact vaccines being rolled out in the UK but he hoped the inoculations would continue to protect against severe illness.
Prime minister Boris Johnson said the government continues to “work closely” with its Indian counterparts to “determine what further help they may need”, as a devastating surge of new infections continues to tear through the country.
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