According to a new study, the efficacy of the Pfizer/BioNTech vaccine drops by 47% after six months.
The research revealed that the Pfizer/BioNTech vaccine was 90% effective against hospitalisation for at least six months regardless of the variant involved but only 47% effective against infection.
The research, which was published in the Lancet medical journal found that reductions in vaccine efficacy were most likely due to waning immunity and not the Delta variant or other new strains of the virus.
Researchers analysed the health records of 3,426,957 people who received the vaccine and discovered that 5.4% had been infected with the virus and 6.6% were hospitalised.
All participants were over the age of 12 with the median age being 45 years old.
A proportion of those who were admitted to hospital were also older men and had underlying health conditions.
The authors of the study noted that there were some limitations to the study such as the vaccination status of the group not being randomised as well as the lack of data on adherence to guidelines, social interactions and occupation for the participants.