Coronavirus cases are trebling in Hertfordshire - but health officials believe the true number of infections are being significantly unreported.

More than 11,000 cases were recorded in the county in the seven days to March 16; many of which is the Omicron variant.

But Hertfordshire County Council believes the actual number of cases could be as much as 50 per cent higher than what's being reported.

Over the pandemic, the Government and public health officials have been testing sewage to determine how prevalent Covid-19 is in communities.

The programme tests samples of wastewater for traces of the virus, with any positive samples undergoing genome sequencing to identify whether it is a variant of concern.

This testing still goes on with a council spokesperson saying: "Based on comparing the testing figures with the results of wastewater monitoring, we estimate that testing is undercounting cases by between a third and a half."

It's thought the removal of Covid restrictions and the imminent end of free mass testing is prompting those with Covid or who test positive for the virus to not actually register their result.

But despite the believed undercount, Hertfordshire's director of public health Jim McManus pointed towards a "significant rise" in case numbers since January with infection rates trebling county-wide to around 1,000 cases per 100,000 population.

This is, in some areas, around half the rate during the Omicron peak over Christmas, but does not take into account cases that aren't being reported.

Mr McManus said: "Is it a further wave? We don’t know. Will it peak any time soon? My feeling is it will peak around Easter, if it keeps going like this."

Infection rates are highest in young to middle-aged adults, Government Covid dashboard data shows, but climbing in all age groups.

With case figures perhaps proving to be unreliable due to lack of reporting, hospital data can provide a more accurate picture of how Covid is affecting patients.

The latest figures reported for West Hertfordshire Hospitals NHS Trust are for March 15 when 63 Covid patients were being cared for, including four on ventilation.

Since the mass emergence of Omicron, the peak of Covid patients at the trust on any single day has been 101 on January 26 - which is still around a third lower than previous waves when we did not have vaccines.

Although the Omicron variant is said to be "milder" than the previous Delta variant, Mr McManus stressed that it was "not mild".

He said that mild only meant that hospitalisation was not required – and that there are a lot of cases where Omicron has left people with a severe coughing and other symptoms for several weeks.

He also warned that hospitals are seeing unvaccinated patients in their 30s and 40s being admitted with Covid.

Mr McManus says there are four measures people can do to avoid disruption and minimise the spread of the infection.

He urged everyone to be vaccinated – or boosted, if eligible – as he said this would reduce severe disease, and also recommended the ventilation of offices, homes, premises and leisure facilities – as well as the wearing of face masks in crowded areas.

And he said people should remain at home if they had symptoms that were consistent with Covid.

As of March 21, 63 per cent of over 12s in Hertfordshire have been boosted against Covid, with just under 80 per cent double jabbed, and 16.5 per cent unvaccinated.