Similarities:
* Goal: Both Salk and Sabin aimed to create a vaccine that would protect people from polio, a debilitating and sometimes fatal disease.
* Focus on Prevention: Both recognized the importance of preventing polio rather than treating it.
* Impact: Both vaccines had a profound impact on public health, leading to a dramatic decline in polio cases worldwide.
Differences:
1. Vaccine Type:
* Salk: Developed an inactivated polio vaccine (IPV). This vaccine uses poliovirus that has been killed, making it unable to cause disease but still stimulating an immune response.
* Sabin: Developed an oral polio vaccine (OPV). This vaccine contains live, weakened poliovirus that, when ingested, replicates in the gut but does not cause disease, stimulating immunity.
2. Administration:
* Salk: Administered by injection.
* Sabin: Administered orally (by mouth).
3. Effectiveness:
* Salk: Very effective at preventing paralytic polio but not as effective at preventing infection.
* Sabin: More effective at preventing both infection and paralytic polio. It also offers some protection against poliovirus spread in the community.
4. Challenges:
* Salk: Requires multiple injections and a cold chain (refrigeration) for storage and distribution.
* Sabin: Can occasionally revert to a virulent form, causing vaccine-associated paralytic polio (VAPP). However, this risk is very low, especially in developed countries with high vaccination rates.
5. Timeline:
* Salk: First licensed in 1955.
* Sabin: First licensed in 1961.
In Summary:
Both Salk and Sabin made significant contributions to polio eradication, but their approaches differed. Salk's inactivated vaccine was a breakthrough that helped control the disease, while Sabin's oral vaccine provided broader protection and facilitated global eradication efforts. Today, the use of IPV and OPV, along with ongoing vaccination programs, continue to protect against polio and maintain a high level of immunity worldwide.