The US Department of Health and Human Services has warned that a “preliminary” study of the coronaviruses COVID-19 vaccines that have been distributed in the US suggests they may have triggered a “significant number of new infections.”
“We’re not yet sure what’s causing these cases, but the potential causes are very substantial,” the Department of Homeland Security’s Centers for Disease Control and Prevention wrote in a report obtained by Wired.
“The potential causal relationship between vaccination and these infections could be the result of multiple agents acting simultaneously, as we are now learning in other coronaviral coronavireases, including COVID,” the report said.
As a precaution, CDC officials will be “continually reviewing the effectiveness of these vaccines to assess whether they are effective against COVID outbreaks,” it added.
US healthcare systems will be closely monitoring COVID cases to make sure they do not increase, as “a small number of cases” may be linked to vaccinations, the agency added.
The report was made public on Monday, just days after the US Centers for Medicare and Medicaid Services (CMS) said the COVID vaccines had been given to more than 16 million people, bringing the total number of US citizens to more or less 100 million.
The vaccine, which was first administered in March, has been a source of contention between healthcare providers and the pharmaceutical industry, with some concerned about the potential for COVID to contaminate their drugs and the efficacy of the vaccines, which have been sold for decades in the United States.
However, the US has been immune to coronaviroids before, with the virus first infecting the United Kingdom and then the Netherlands in 1957.
The coronavirin vaccines, developed in the 1960s, were initially administered in the early 1990s.
But in 2007, US health authorities warned that they had been contaminated with a virus that could infect humans, and a total of 15 people died in that outbreak.
In the following years, COVID infections were found to have been spread from vaccine recipients to patients who had not been vaccinated.