Health experts have warned the Covid-19 pandemic "isn't over", as a county saw cases rise by 20% in a week and an increase in people going to hospital.
In the week to 22 June, Northamptonshire has 886 cases, up from 736 in the previous week.
The county's two councils said two new subvariants of Omicron appeared to be more infectious than other variants.
Both North Northamptonshire and West Northamptonshire councils said there was an increase in hospital admissions from the rise in cases.
Northampton General has 16 people in hospital with Covid-19 - an increase from 13 in the previous week, and Kettering General has 21 in hospital - a rise from 17.
Public health officials at the authorities said residents should try to meet outdoors, and ventilate homes and workplaces when meeting indoors.
They also said those who test positive should isolate - and with the Omicron variant, and the two new subvariants known as BA.4 and BA.5, there was a higher risk of reinfection.
Ms Burns said: "I think some people are maybe letting their guard down a bit.
She warned that some people were "still becoming quite poorly with Covid".
But she added that although cases had risen, they were "nowhere near as high as we've been".