Israel is offering a third dose of a COVID-19 vaccine to people who are immune compromised. Since April, France has encouraged the same for transplant recipients, dialysis patients and those on powerful immune-compromising medication. Vaccine companies are studying the effectiveness of a third shot – either identical to the first two or tailored to a variant. So it becomes logical to ask whether Americans need booster shots to protect against the new variants, including delta, first seen in India. For now, the government has said boosters aren't needed. A third shot hasn't been proven safe or effective yet, and there are many vulnerable people across the world who haven't yet had the first dose of a vaccine.