Pointing out at a gene called HLA-DQB1*06, scientists say ‘About 30 to 40% of the UK population have this type.’
The people who carry this gene are less likely to experience a "breakthrough infection" over this time period. But there are many other factors that contribute to the risk of getting Covid, including age, other illnesses and people's occupations.
They found those who had the gene variant were less likely to experience a "breakthrough infection" over this time period, where people still got a mild Covid infection after vaccination.
The study, published in Nature Medicine, might need more research to confirm the theory.
Dr Alexander Mentzer, NIHR academic clinical lecturer at the Wellcome Centre for Human Genetics and a lead researcher on the study, said: "We have seen a wide variation in how quickly people test positive for Covid-19 after vaccination.
"Our findings suggest that our genetic code may influence how likely this is to happen over time.
"We hope that our findings will help us improve vaccines for the future so they not only stop us developing severe disease, but also keep us symptom-free for as long as possible."
Lead researcher Prof Julian Knight added: "From this study we have evidence that our genetic make-up is one of the reasons why we may differ from each other in our immune response following Covid-19 vaccination.
"We found that inheriting a specific variant of an HLA gene was associated with higher antibody responses, but this is only the start of the story.
"Further work is needed to better understand the clinical significance of this specific association," he added. "And more broadly what identifying this gene variant can tell us about how effective immune responses are generated, and ways to continue to improve vaccines for everyone."
However, it is yet to be understood whether the findings are applicable to more ethnically diverse populations, as the different population has different levels of the gene variant.
