Sir: As amid a recent upsurge in attacks on efforts to protect children from the crippling disease, a woman polio worker was killed and another injured in an attack in the Chaman area. In Rawalpindi, a polio team was thrashed and barred from vaccinating children in the Pirwadhai area by six members of a family, which led to the registration of a criminal case against them. After the Rawalpindi incident, police registered an FIR on the complaint of sub-inspector. Our concern authorities must draw modus operandi to save polio workers. MUHAMMAD NATIQ Karachi