'NEED FOR CONTINUED VIGILANCE' It is understood that a further drive to get all adults vaccinated is underway and mobile jab vaccine units could be on the streets soon. Scientists believe the Delta mutation is more easily transmissible and “fitter in human airway cells,” meaning there is likely to be more of it in an infected person - so there is more to spread. Dr Gerry Waldron, head of health protection at the PHA, said: "The spread of the Delta variant underpins the need for continued vigilance and adherence to the public health guidance. "It is essential that people continue to work w...