Health chiefs say they are "monitoring" a number of "small" covid-19 outbreaks in Northamptonshire care homes.
Latest official numbers from Public Health Northamptonshire showed recent outbreaks in ten homes spread across the county, compared to just three last week.
But the county's Public Health director, Lucy Wightman, says that: "Care home related cases, thankfully, remain much lower than at the height of the pandemic.
"This is testament to the hard work of care home staff, the continued regular testing and the effectiveness of the vaccination roll out in Northamptonshire."
Officials are unable to make public which homes are involved but four are in Kettering, which currently has the highest case rates in England at nearly double the national average.
Three more are in Northampton, two in Corby and one in South Northamptonshire.
Two deaths among care home residents in West Northamptonshire were recorded by the Office for National Statistics within the last two weeks.
The county's Public Health director, Lucy Wightman, said: "We track all of the county’s known outbreak situations and take action to manage the coronavirus in our communities.
“We are aware of outbreaks in several care homes and are providing residents and staff with appropriate guidance and support. We are working with the local public heath team, UK Health Security Agency and Environmental Health colleagues to closely monitor these situations.
“Although we have seen an increase in outbreaks, thankfully where these occur we are only seeing small numbers of cases as these are picked up by routine lateral flow device testing, which means they are identified early and contained.
“There is no doubt that regular testing and vaccination of care home residents has protected, and continues to protect, some of Northamptonshire’s most vulnerable residents from serious illness and death.
“The rollout of booster vaccinations to eligible residents has already started in the county, and will continue as residents become eligible for their third dose."
Although the ten outbreaks involve just 30 cases, health chiefs will be paying close attention to any rise in a cohort which is more vulnerable to the virus.
Restrictions for seeing friends and family in care homes in England were lifted on 19 July although visitors were "strongly recommended" to be fully vaccinated.
The government also said it wanted all care workers to be fully vaccinated by November.
Those who did not have a first jab by September 16 will not be able to meet the government's November 11 deadline to have both jabs and will be unable to carry on working.
According to official figures, 331 care home staff out of 3,755 in North Northamptonshire had not had a jab at all on September 19. The equivalent number in West Northamptonshire is 419 out of 4,311.
Health secretary Sajid Javid told care workers last week: "If you cannot be bothered to go and get vaccinated then get out and go and get another job."
But unions have warned that sticking to the deadline will lead to dangerously low staffing levels in the care sector.