text: hey,suna kya? scientist ne ek aisa vaccine banaya hai jo sirf ek baar lene par hi lifetime immunity deta hai, kya sach mein yeh possible hai?haan yaar, mujhe bhi suna tha, lekin soch rahi thi ki kya side effects toh nahi honge, kyunki koi bhi cheez perfect nahi hoti, right?