There were 2,703 excess deaths across England and Wales in September, official figures show – but coronavirus was not in the 10 leading causes of fatality.
The numbers released by the Office for National Statistics (ONS), are relative to the five-year average, counting from 2015 to 2019.
The leading cause of death in September for both nations was dementia and Alzheimer’s disease.
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However, coronavirus was the underlying cause of death in 11.5% of all deaths in England and 9% of those in Wales from January to September this year.
But the data also shows more people who caught the illness, died.
The age-standardised death rate in England in September due to COVID-19 was 12.6 per 100,000 people, up from 7.2 per 100,000 in August.
It is the first increase since the pandemic peaked in April, the ONS said, when it caused more than 600 fatalities per 100,000.
The ONS said: “In September 2020, the number of deaths and mortality rate due to Covid-19 remained significantly below levels seen in March 2020 – the first month a Covid-19 death was registered in England and Wales.
“However, the mortality rate due to Covid-19 was significantly higher in England in September 2020 compared with the previous month.”
More than 800,000 people have caught coronavirus in the UK since the start of the pandemic and more than 44,000 of them have died.
As cases have surged again in the second wave, millions of people are facing tougher lockdown rules in the next 24 hours.
Greater Manchester moved into the highest alert level, Tier 3, on Friday morning, and Wales will introduce its two-week “firebreak” lockdown at 6pm.
Coventry, Stoke and Slough will enter Tier 2 on Saturday, while talks between Westminster and civic leaders in Nottingham over possible Tier 3 restrictions are continuing on Friday.
Under Tier 3 measures in Greater Manchester, pubs and bars will be closed, unless they are serving substantial meals, for a 28-day period, along with casinos, bingo halls and bookies.
Chancellor Rishi Sunak has increased the financial support available for businesses and employees affected by the measures, announcing an emergency multi-billion pound bailout on Thursday.
The Job Support Scheme, which replaces the current furlough system from November 1, will be made more generous in an effort to persuade firms to keep staff in work.
There will also be grants of up to £2,100 a month available for firms in Tier 2 areas of England, aimed at helping hospitality and leisure venues which have seen takings plummet due to restrictions on households mixing.
Analysing sewage for traces of coronavirus is helping officials spot outbreaks in areas where relatively few people have been tested.
The government-led scheme is detecting fragments of genetic material from the virus, which pass out from people’s bodies when they use the toilet.
Weekly deaths linked to coronavirus have risen to their highest level in England and Wales since the beginning of July, the agency said earlier this week.
A total of 438 deaths were registered in the week ending 9 October with COVID-19 mentioned on the death certificate, up from 321 deaths in the week to 2 October.