People aged 60 to 69 have been advised on Thursday by Germany’s Robert Koch Institute (RKI) for infectious diseases to get a second booster dose of Covid-19 vaccine.

RKI’s standing committee on vaccination updated Covid-19 vaccination guidelines to review the age threshold for those who need a fourth shot down to 60 from 70.

The committee also recommended that kids aged over 5 require another booster in the event that they have an underlying condition.

The second booster shot should not be taken earlier than six months after the previous immunization or recovery from the coronavirus.

The World Health Organization’s strategic advisory group of experts in immunization (SAGE) said Thursday that only people at risk should be given a second booster dose. SAGE head Alejandro Cravioto also noted that revaccinating all adults or children is not needed.

Read: WHO: Europe must act now or risk stricter Covid measures