Blackburn with Darwen Council public health director, Prof Dominic Harrison, writes his weekly column for the Lancashire Telegraph

ON June 29, the government finally allowed local directors of public health to have the postcode level data of confirmed Covid-19 cases within their local authority.

We are to get more control over local testing capacity from August. This will allow us to warn and inform local communities more accurately about the local situation and manage the virus spread more effectively.

From the data we have now, we can be more specific about local risks.

In phase one of the local pandemic, the first cases of Covid-19 appeared in late February and early March. Then, the virus principally affected older, wealthier, ethnically ‘white British’ people who were infected abroad and returned to the UK from holidays in Italy, France and Spain. The index case (the first person infected) often infected their own immediate family members through household transmission.

In the second phase during March and April, most were infected both by wider community spread and within hospitals and care home settings. Those infected were from broader population groups, but into early June, it became clear that front line workers in various occupations, who were more exposed to more people, were showing much higher rates of infection, as were black Asian and minority ethnic communities – themselves also more likely to be in front line jobs.

As we enter July, the numbers of people infected with Covid-19 in hospitals and care homes have fallen dramatically due to massively improved testing and infection control measures. Newly confirmed cases are down to less than 10 a day in most Pennine Lancashire local authorities.

However, in this third phase of the pandemic, we can see a higher percentage of those newly-diagnosed over the past two weeks are from South Asian heritage communities. There is a clustering of cases in larger multi-generational households in areas characterised by smaller terraced housing. In some ways it looks like this pattern of spread has returned to the start - smaller numbers with an index case infecting their whole family through household transmission.

Pennine Lancashire has a much higher percentage of households with five or more members than the UK. Blackburn with Darwen has 11.7 per cent, Pendle 8.8 per cent, Hyndburn 7.3per cent - the northwest regional average is 6.4 per cent. The average age of infection is also falling and there is some evidence of younger people struggling more than most to maintain social distancing guidelines.

So there is a raised risk here for multi-generational households – particularly those where older or clinically vulnerable members will be at more risk of serious effects.

Continued social distancing, improved household hygiene, testing and separation of symptomatic household members and longer term improvements to overcrowded housing are going to be key interventions to control this local ‘clustering’ effect.

Mass gatherings in enclosed public spaces remain the highest risk – particularly as larger numbers can be infected from a single case. As pubs, hospitality venues and places of worship open and holidays begin, the pattern of spread may change yet again as more of us meet more people.

We need to look after each other, support each other to social distance, and report symptoms if we have them.