MedicalHiranyagarbha · Class 11-12
Teeka baazu mein, training poori body ki
Ek suee, do minute — aur body saalon tak ek bimaari ko pehchaan-ne lagti hai. Yeh yaaddasht banti kahan hai?
Socho pehle… phir dekho jawab
Vaccine bimaari nahi deti; woh sirf pehchaan ka namoona (antigen) deti hai — mara hua ya kamzor rogaanu, uska ek hissa, ya uska blueprint. Body us par poori practice-drill chalati hai aur memory cells bana kar rakh leti hai.
Antigen ko dendritic cell jaisi 'antigen presenting cell' pakad kar helper T cell (CD4) ko dikhati hai. Woh do taraf signal deta hai — B cells ko, jo plasma cells ban kar antibody banati hain, aur cytotoxic T cells (CD8) ko, jo infected cells ko khatam karna seekhte hain. Baad mein kuch memory B aur memory T cells bach jaati hain — isliye pehla response dheema, aur doosra (booster par) tez aur mazboot.
Ek model jo poore mohalle par lagta hai: herd immunity threshold ≈ 1 − 1/R₀, jahan R₀ batata hai ki ek bimaar vyakti bina rok-tok kitne logon tak bimaari pahunchata hai. R₀ = 5 par 80% logon ka immune hona chahiye; measles jaisi bimaari mein yeh aur oonchi. Matlab teeka us bachche ki bhi suraksha hai jo umar ya bimaari ki wajah se khud teeka le hi nahi sakta.
Aur pata kaise chalta hai ki vaccine sach mein kaam karti hai? Clinical trials se: Phase 1 chhote group par safety, Phase 2 dose aur immune response, Phase 3 hazaaron logon par randomised trial jismein aadhon ko placebo milta hai aur aksar na mareez ko na doctor ko pata hota (double blind), aur Phase 4 approval ke baad ki nigraani. Trade-off: jitni jaldi vaccine chahiye, utna kam samay data jama karne ko. Aur haan — tabiyat theek na lage toh bade ko batao aur doctor ko dikhao.
Ghar pe try karo
Ghar mein kisi chhote bachche ka immunisation card dhoondho (ya apna purana). Likho ki kaunsa teeka kis umar par lagta hai aur kis par booster doosri baar aata hai. Phir socho — booster kyun? Jawab upar wale secondary response mein hai.
Wow!
Body 'yaad' rakhti hai bina dimaag ke — memory B cells khoon mein saalon tak ghoomti rehti hain, sirf ek naam pehchaanne ke liye.
3 sawaal
- Antibody banane wali cells kaunsi hain?
Jawab dekho
B cells se bani plasma cells. B cells activate hokar plasma cells banti hain, jo antibody banati hain; T cells ka kaam alag hai.
- R₀ = 4 ho toh herd immunity threshold lagbhag kitna hoga?
Jawab dekho
75%. 1 − 1/R₀ = 1 − 1/4 = 0.75, yaani 75%.
- Phase 3 trial mein placebo group kyun rakha jaata hai?
Jawab dekho
Taaki pata chale ki sudhar vaccine se hua ya waise bhi ho jaata. Comparison group ke bina yeh alag nahi kiya ja sakta ki asar dawa ka tha ya sirf samay aur ummeed ka.
NCERT se jodo: NCERT Class 12 Biology — human health and disease (immunity, vaccination aur immunisation)