The UK has recorded 35,847 new COVID cases and 149 more coronavirus-related deaths in the latest 24-hour period, government data shows.
The figures compare with 30,838 infections and 174 fatalities recorded yesterday - the highest daily death total since 12 March.
This time last week, 18 August, 33,904 cases and 111 deaths were announced.
Since the pandemic began, 132,003 people in the UK have died within 28 days of testing positive for COVID-19 and there have been 6,590,747 lab-confirmed cases.
According to the latest data, 859 COVID patients were admitted to hospital on 21 August and there were 6,172 admissions in the last seven days, a rise of 9.4% on the previous week.
On Tuesday, 55,410 people were given their first dose of a COVID-19 vaccine, taking the total to 47,792,552 - equivalent to 87.9% of the UK's adult population.
Also, 130,676 people were given their second dose, which means 42,072,712 (77.4% of adults) are now fully inoculated.
It comes as new research has found protection from two doses of the Pfizer or AstraZeneca vaccines begins to wane within six months.
In a reasonable "worst-case scenario", protection could fall to below 50% for the elderly and healthcare workers by winter, analysis from the Zoe COVID study found.
Professor Tim Spector, the lead scientist on the app, told Sky News that protection from vaccines is falling by around 3% per month.
Speaking about plans for a booster campaign, Mr Spector says this will have to be done with "precision" to avoid wasting vaccines as having COVID is like having a booster, in terms of impact on immunity.
He said booster jabs should be prioritised over vaccinating children if the UK wants to reduce deaths and hospitalisations.
Meanwhile, more than 1,000 people who attended Latitude Festival last month have tested positive for the virus.
The festival, which ran from 22 to 25 July, was part of the government's Events Research Programme and was attended by about 40,000 people.
Festivalgoers had to show proof of a negative COVID-19 test or be double vaccinated to access the site at Henham Park in Suffolk.
However, data released by Suffolk County Council reportedly shows 1,051 people tested positive for the virus in the days after the event.
It follows the news yesterday that health officials are investigating 4,700 cases of COVID which are suspected to be linked to the Boardmasters music and surf festival, which took place nearly two weeks ago in Cornwall.
September is expected to be a key month for the UK on COVID, with the biggest unknown being how much cases and hospitalisations will rise once pupils return to school and people come back from holidays.
The exact size of this rise is uncertain, with one expert saying that how many people end up in hospital is the "biggest unknown".
Dr Mike Tildesley, a member of the Scientific Pandemic Influenza Group on Modelling (Spi-M) which advises the government, said: "Probably what we will see is maybe in the middle of September we might see cases picking up a little bit and it may take a week or two or more for that to spill over into a rise in hospital admissions."