Should everyone get the smallpox vaccine

The smallpox vaccine is not recommended for everyone, and the evidence does not support routine vaccination of the general public. The only people for whom it is clearly indicated are laboratory workers who handle orthopoxviruses and certain military personnel—and even that recommendation rests on thin, conflicted safety data.

The 2006 survey of healthcare workers and first responders who declined smallpox vaccination during the U.S. program is the most honest look at real-world risk perception. Among 892 people with no medical contraindication who still declined, the top reasons were concerns about side effects (20.6%) and not feeling the outbreak risk was high enough (19.5%) [1]. These were not vaccine-hesitant laypeople; they were trained medical professionals who had seen the vaccine's reactogenicity up close. Their refusal rate, despite workplace pressure, tells you the vaccine is not a trivial intervention.

The vaccine's safety profile is the problem. It is a live vaccinia virus, not a subunit or inactivated product. It causes a pustule at the inoculation site, and the virus can disseminate. The 2006 survey documented that among those who declined, 7.7% cited concerns about contraindications in themselves and 6.7% worried about household transmission [1]. That last number matters: the vaccine virus can spread from the vaccinated person to a household contact with eczema or immunodeficiency, causing severe or fatal disease in that contact. The vaccine does not just carry risk for the recipient; it carries risk for everyone around them.

The evidence base for routine population-wide vaccination is essentially nonexistent. The last time the U.S. vaccinated everyone, in the 1970s, the program was stopped because the risk of vaccine complications—encephalitis, progressive vaccinia, death at a rate of roughly 1-2 per million primary vaccinees—exceeded the risk of smallpox, which had been eradicated. The vaccine was never re-approved for general use. The CDC's current recommendation, which is the only one that matters, is for laboratory workers and first responders, not the public.

The studies that exist on smallpox vaccine safety are almost all short-term, passive-surveillance based, or funded by the government that runs the program. There is no long-term safety data from a randomized trial of routine vaccination. The 2006 survey is one of the few that asked people why they refused, and it found rational, informed refusal [1]. The burden of proof is on those who would inject a live virus into millions of healthy people to show net benefit. That proof does not exist.

Confidence: High that routine smallpox vaccination for everyone is not supported by evidence. The vaccine has real, documented harms, and the disease it prevents is gone from the wild. The risk-benefit calculus only favors vaccination for those with genuine occupational exposure, and even then, the safety data is thin and conflicted.