The Telegraph reports the data, being studied by health secretary Sajid Javid, shows that at the end of last month, only 0.4% of vaccinated travellers arriving back from holiday at UK airports had contracted the virus.
Arrivals jabbed only once were twice as likely to test positive, representing 0.8% of arrivals.
According to the analysis by testing firm Cignpost Diagnostics, which reportedly conducts 11,000 tests on arrivals a day, only between 1 and 1.2% of unvaccinated holidaymakers also tested positive.
The new statistics come as pressure mounts on the government to ease the PCR testing regime, and get a grip on "cowboy" practices among testing providers.
Last month, Huw Merriman MP, chair of the Transport Select Committee, claimed only a fraction of test results were being genomically sequenced, describing the market as a "rip-off".
On Wednesday (25 August), the Competition and Markets Authority (CMA) warned some testing firms they could be breaking the law after Javid instructed the watchdog to investigate the "exploitative behaviour" and "unfair practices" of some of the providers listed on the government website.
