Johnson's remarks were made as he introduced legislation designed to block vaccine mandates.

(Reuters) - U.S. Republican Senator Ron Johnson used health data gathered in England to claim more vaccinated people have been seriously affected by the Delta COVID-19 variant than the unvaccinated. Johnson’s statements, and subsequent social media posts sharing them, do not explain the details underlying the data quoted, however.

Social media posts featuring the clip have attracted hundreds of thousands of views.

Johnson’s remarks were made as he introduced legislation designed to block vaccine mandates, which he argues are an “outrageous trampling of civil liberties”

“President Biden, and this has been parroted by media, news media, said that what we are currently experiencing is a pandemic of the unvaccinated. They don’t give us really any data to back that up,” Johnson said during the introduction.

Johnson went on to present figures from a Public Health England (PHE) document published on September 17.

The document is a technical briefing that tracks “SARS-CoV-2 variants of concern and variants under investigation in England”. It does not show all cases of the virus detected in England, rather those in which the patient’s sample was sequenced or genotyped to determine the variant. Charts within the document show that the percentage of overall cases analyzed in this way has varied greatly over recent months.

Total UK coronavirus cases and deaths can be viewed on the government’s dashboard and can be broken down by nation.

Page 16 of the document referenced by Johnson shows 593,572 total Delta cases were confirmed by sequencing or genotyping between Feb. 1, 2021 and Sept. 12, 2021. The number of deaths recorded among these cases was 2,542.

On page 20, this figure of 2,542 is broken down by vaccination status. Among the fully vaccinated (more than 14 days after a second dose) there were 1,613 deaths (63.4% of the total). Among the unvaccinated there were 722 deaths (28.4% of the total). The remaining deaths were among the partially vaccinated.

“In England, of the 600,000 new cases of Delta, of the over 2500 deaths, 63% of those deaths, 1613 people, were the fully vaccinated. 28% were with the unvaxxed,” Johnson said. “This is information that the American people have probably never heard.”

A summary on page 3 of the same report states: “2 doses of the vaccine remain highly effective, with 60 to 85% effectiveness against infection, 90 to 99% effectiveness against hospitalization, 90 to 95% against mortality and 65 to 99% against symptomatic disease”.

Social media posts were fact checked earlier questioning why more cases and deaths might be reported amongst a vaccinated population than an unvaccinated one.

“The data should be interpreted taking into consideration the context of very high vaccine coverage in the UK population. Even with a highly effective vaccine, it is expected that a large proportion of cases would occur in vaccinated individuals, simply because a larger proportion of the population are vaccinated than unvaccinated,” a spokesperson for PHE previously told Reuters via email.

Dr Muge Cevik, a clinical lecturer in infectious diseases and medical virology at the University of St Andrews, also told Reuters that when much of a population has been vaccinated, “most infections and deaths are expected to be among those vaccinated”.

England’s prioritization of vulnerable individuals and older populations early on in its COVID-19 vaccine rollout may also play a part.

In a COVID-19 vaccine surveillance report published on Sept. 23, PHE estimates that 123,100 deaths have been prevented as a result of COVID-19 vaccine delivery, and gives details about how this figure was calculated.

The use of data from England in a consideration of the situation in the U.S. also fails to reflect the difference in vaccination rates between the two countries.