Are London’s Covid-19 hotspots linked by the UNDERGROUND?

London’s Covid-19 hotspots could be linked by the city’s bustling underground network, according to a striking map based on government data.

Coronavirus cases are spreading across the capital and ministers are now said to be mulling a decision to place more than 9million people in the city. 

MailOnline can reveal the cluster of cases appear to be centered along the 11 Tube-lines — used by some 2million people every day before the pandemic struck. 

It means areas in the north west and north east of London may be suffering from bigger outbreaks than the south, simply because they have more public transport links. Bexley, Bromley, Croydon, Kingston upon Thames, and Sutton — none of which have a Tube station —  have the lowest infection rates across the entire city.

The connection has previously been discovered by experts looking at other contagious respiratory diseases that spread via droplets, such as the coronavirus. British scientists have previously linked busy Tube stations to worse flu outbreaks.

The more changes passengers needed to make on their journey, the more contact they were likely to have with other people. This would potentially be the case with London’s three top hotspots — Redbridge, Hounslow, and Barking and Dagenham — all of which are only served by one Tube line.

Nine of 32 boroughs which were found to have higher cases of the flu, based solely on their London underground connections, now also have higher Covid-19 infection rates. Scientists say the Tube is the ‘perfect environment’ for a virus to spread because of crowding, poor ventilation and dirty surfaces touched by millions.

But experts say the pattern may be more complicated than that — it may be more key workers, who are vulnerable to picking up the virus because they come into close contact with lots of people, choose to live near a Tube line in order to get around easier, while those able to work from home live further out in the suburban commuter belt. 

Infection rates may also be heavily influenced by the borough’s deprivation, as Government studies have shown poorer areas have been shown to have more Covid-19 deaths, and ethnic diversity, as Black, Asian and ethnic minorities have been harder hit by the pandemic for a multitude of reasons.

Millions of travellers were put off the tube during the peak of the first wave of the coronavirus because the Government ruled against any travel other than essential. 

But since restrictions have been lifted in response to the outbreak dwindling, hundreds of thousands more journeys are now being made. Tube capacity has risen to around 35 per cent, up from four per cent in April and May. Cases also appear to keep rising in London alongside the uptick in journeys. 

It comes as MailOnline yesterday revealed that cases have actually started to plateau across London and are now only rising in a handful of boroughs, including Redbridge. Hospital admissions have tripled in a fortnight but are still a far cry from the 400-plus being recorded a day back in March, before the national lockdown was imposed. 

London’s Covid-19 hotspots could be linked by the Underground network, a striking map reveals. Pictured are the infection rates in London’s boroughs, given by the Public Health England report on Friday 18

The London Underground in closer detail: The colours show different tube lines and where they do and don’t extend to

Scientists have speculated numerous reasons that could explain why some boroughs are being hit harder than others. And one could be how integrated public transport is in those boroughs.

When University College London (UCL) and University of Bristol speculated this for flu-like illnesses in 2018, their theory turned out to be correct.

The researchers compared Oyster card route information and Public Health England data on flu-like illnesses over six months in 2013/14.

Boroughs with fewer stations had higher infection rates as these tend to be more crowded, the academics wrote in the paper, published in the Environmental Health journal. 

‘Higher rates [of influenza-like cases] can be observed in boroughs served by a small number of underground lines,’ said lead author Dr Lara Goscé said at the time.

‘Passengers starting their journey in these boroughs usually have to change lines once or more in crowded junctions… in order to reach their final destination.’ 

Commuters in boroughs further from central London spend longer on the underground — potentially coming into contact with more infected people. Having to change at a busy stop increases the danger.

There are 32 boroughs in London. Nine which were found to have higher cases of the flu, based on their London Underground connections, now also have higher Covid-19 infection rates. 

These are Barking and Dagenham (29.3), Enfield (27.3), Newham (27), Hackney (25.7), Tower Hamlets (25.5), Harrow (24.4), Wandsworth (23), Brent (22.7) and Waltham Forest (21).

Some of these boroughs on London’s outskirts and commuters must pass through stations such as Waterloo, the busiest underground in the capital, which serves 100.3million passengers every year.

On the other hand, commuters in the five areas with no Tube stations at all — Bexley, Bromley, Croydon, Kingston upon Thames and Sutton — saw fewer cases of flu-like illnesses over the six-month period.

Lewisham was an exception, which the researchers — who published their original flu study in 2018 — said may be because it has a number of railway stations.

The same pattern has now clearly presented itself with Covid-19. Infection rates in Lewisham (15.8), Kingston upon Thames (14.3), Croydon (14), Bexley (12.1), Bromley (11.8) and Sutton (9.3) are among the lowest in the city. 

They are joined by Merton (13.6), the last stop of the Northern line in the south, Westminster (14.9), which is more central and has two lines passing through, Hillingdon (16.1), at the end of both the Metropolitan line and the Piccadilly line, and Islington (15.9), on the Victoria line and Overground.

If a borough that is well connected, and often crowded, has lower rates of flu-like illnesses, it could be because people living in those boroughs don’t actually use the tube to get around, Dr Goscé and colleagues said.

They may simply walk (such as in Westminster), or use a car (in Merton). 

Keith Neal, an emeritus professor of the epidemiology of infectious diseases, University of Nottingham, told MailOnline: ‘For some of the very central boroughs people would not need to use the tube to get to work. 

‘Clearly mass transport could pose risks, but how many of these residents use the Tube rather than buses? On a bus your droplets hit the seat in front of you, on a tube they go in all directions.

‘It would not surprise me if it is a risk factor; look at other major cities that got hit with Covid-19 – many were financial centres.’ 

Professor Paul Hunter, an infectious disease expert at the University of East Anglia, said studies linking flu and the London Underground are ‘pretty low down the hierarchy of evidence and cannot be used to prove anything’ because they cannot prove causation.

‘Nevertheless its conclusions are probably not surprising and I doubt anyone would argue against the suggestion that flu spread on the underground especially when the trains were crowded,’ he told MailOnline.  

London’s Covid-19 hotspots may be explained by deprivation. This map shows the areas where poverty affects more than 30 per cent (light blue) and 40 to 45 per cent (dark blue) of residents

There are, as expected, some boroughs that buck the observed trend. 

Greenwich, in south-east London, was noted by the original UCL study as an area with the highest flu-like influenza cases. However, Covid-19 infections are on the lower end of the scale, with a rate of 16.1.

The borough is served by the Jubilee line and the DLR, but commuters generally have to change line at least once to reach their end destination. 

Residents in Redbridge and Hounslow, with the first (34.2) and second (32.5) highest Covid-19 rates in the capital, were not noted by UCL as being at risk of respiratory illness due to their tube stations.

Redbridge is served by the Central line, while Hounslow is on the Piccadilly line, and the data showed commuters did not come into contact with high numbers of people in their journeys. However both will be used by thousands per day. 

Therefore, other factors that influence an area’s Covid-19 infection rate may be at play there.

For example, Hounslow and Redbridge both have some of the most ethnically diverse populations in London — and it has been found that people of Black, Asian and ethnic minorities (BAME) are at higher risk of catching Covid-19.  

Experts blame this on the fact they are more likely to work key worker jobs, such as in hospitals, live in areas with crowded housing where contact with Covid-19 cases may be more likely, and have more underlying health conditions that exacerbate infection. 

Figures show infections have tripled in Redbridge since September 4, when the rate was 11.2 per 100,000 per week, and have risen by tenfold since the start of August (3.3)

The east London borough of Barking and Dagenham is suffering 29.3 infections per 100,000, having more than doubled since the start of the month, when the case rate was 12.3 per 100,000, and quadrupling since August 1 (5.9 per 100,000)

The west London borough of Hounslow has been the second worst-hit region in the capital, with a weekly case rate of 32.5 per 100,000 in the week ending September 18

London is thought to be on the brink of a localised lockdown after public health chiefs warned of a ‘rising tide’ of the virus in the capital. More than 500 people are being diagnosed in London every day, more than double the number in August

Covid-19 hospital admissions in the capital have tripled in a fortnight, with the seven-day average rising from 11 on September 2 to 33.4 by September 18. But the number of hospitalisations in the city is still a far cry from the 700-plus at the height of the pandemic in spring and only slightly higher than they were the start of July (around 25), when the country was deemed safe to reopen again

Experts blame this on the fact they are more likely to work key worker jobs, such as in hospitals, live in areas with crowded housing where contact with Covid-19 cases may be more likely, and have more underlying health conditions that exacerbate infection.

London’s Covid-19 hotspots may be connected by various other factors.

For example, research has shown that Covid-19 is hitting the poorer areas harder, with residents in Brent, Barking and Dagenham, Newham, Harrow and Hounslow all earning less than the London average wage, and being at higher risk of Covid-19. 

Professor Seif Shaheen, an respiratory epidemiologist at Queen Mary University, highlighted to MailOnline London’s hotspots bared similarities to a map of deprivation in the capital, provided by Trust for London. 

While Dr Saffron Karlsen, who teaches about ethnicity and citizenship at the University of Bristol, said she did not think too much blame could be placed on the Tube.

She told MailOnline: ‘I think the tube might exacerbate the problem, but it probably doesn’t cause it. I suspect it’s more likely down to job or other health inequalities.

‘It would also make sense to consider the people who might be (still) using the tube. I would imagine that tube use has gone back up recently for everyone in London, but there are still some people who are more able to work from home than others (or use their cars if they have to travel). 

‘As such, it may simply be that those more at risk of getting the virus – key workers – are also more likely to be those using the tube.

‘That said, there could be grounds to suggest that the tube could facilitate the spread of the virus. 

‘Closed spaces, a lack of ventilation and limited social distancing – common experiences on the tube – are key to transmission. 

‘I would also imagine that the pressure of the timetable make it difficult for surfaces to be cleaned very regularly. So, the tube would probably be a good place to spread it.’

It’s also important to note that the ‘hotspots’ of London change when looking at cumulative cases compared with cases right now, but not by all that much.   

South-London borough Croydon has had the most Covid-19 cases of all London boroughs, at 2,179 until September 21. Bromley is also on the higher end of the scale, with 1,800 cases. But neither location has an Underground station.

Brent and Ealing have had more than 2,000 cumulative cases and are both have infection rates on the higher end of the scale, over 20 cases per 100,000.  

But due to testing restraints early in the pandemic, prioritising only those in hospitals and seriously sick, and therefore the elderly, the case numbers will be somewhat skewed due to different age, ethnicity and other demographics in each area. Although to what extent is difficult to assess. 

Britons were told to avoid using public transport unless absolutely essential during the strictest days of lockdown, resulting in its use plummeting by around 90 per cent. Now, people in the UK can use the services whenever they please as long as they wear a mask or face covering.

But they are advised to travel at off-peak times, take less busy routes, use contactless payment to avoid touching others and keep one metre apart from other commuters.

Research suggests that, if masks are worn and social distancing is adhered to, the chance of the virus spreading on public transport is minimal.