In 1988, because of the Sri Lankan Civil War, Peiris went back to Newcastle upon Tyne to become a consultant virologist at the Royal Victoria Infirmary.
Peiris's return to Newcastle upon Tyne in 1988 was prompted by the Sri Lankan Civil War, leading him to take on a role as a consulting virologist at the Royal Victoria Infirmary, where he could apply his skills in fighting infectious diseases.