A study found that the effectiveness of two doses of Pfizer or AstraZeneca vaccine on the Delta variant (Indian variant) is almost the same as on the Alpha variant (UK variant). The study also emphasized that if the vaccine is given only one dose, the protection is greatly reduced.
The research was published in New England Journal of Medicine. Researchers surveyed 19,000 people and found that two doses of Pfizer were 88% effective in preventing the symptoms of infection with the Delta variant, while the efficacy against the Alpha variant was 93.7%; the two doses of AstraZeneca were 67% effective against the Delta variant, and also This is close to 74.5% of the Alpha variant.
With only one injection, Pfizer’s effectiveness against the Delta variant is 36%, and AstraZeneca is 30%.
In May this year, the health department “Public Health England (PHE)” has presented the analysis results, referring to the early evidence of actual vaccine application data, indicating that the two doses of AstraZeneca and Pfizer are effective against Delta, and the level of protection achieved is comparable to that of Delta. The level of protection against Alpha is similar. This study can be regarded as confirming the results of PHE in May.
The researcher pointed out that the data this time also reflects that the priority arrangement for two injections can effectively fight the epidemic.
The Wuhan pneumonia variant virus strain Delta, which was first discovered in India, is more infectious and continues to spread around the world, causing the epidemic to rebound in many regions. At present, the Delta virus is the most mainstream spreading version in many countries in the United Kingdom and the United States.