💉✨ In 1967, a needle-free injection method called the jet injector was widely used for mass vaccinations. This device delivered vaccines through a high-pressure stream that penetrated the skin without a traditional needle. ✅ 🌍 It played a big role in large immunization drives like the smallpox eradication campaign, helping healthcare workers vaccinate hundreds of people quickly. ⚠️ However, safety concerns arose later — improper sterilization between uses sometimes led to the spread of bloodbo