A preprint study posted on Friday has found that family members of vaccinated British healthcare workers were around 30 percent less likely to catch Covid-19 than those of unvaccinated workers.

Though a reduction of 30 percent may seem minor, the study pointed out that these family members were also at risk of catching the virus outside the home, making the figure an “underestimate of the ‘true’ effect of vaccination on transmission.”

"We provide the first direct evidence that vaccinating individuals working in high-exposure settings reduces the risk to their close contacts – members of their households."

The study was carried out by researchers at a number of top UK universities and institutions, including the London School of Hygiene and Tropical Medicine, the Imperial College NHS Trust and the MRC Institute of Genetics and Molecular Medicine of University of Edinburgh. Elsewhere, Israeli researchers have also found that US drugmaker Pfizer’s vaccine is 94 percent effective against asymptomatic transmission of the virus, while the US Centers for Disease Control and Prevention has recently loosened its guidelines for people who’ve taken the jab, returning what the press termed “limited freedoms” to this group.

However, health officials in the US have insisted that masking and social distancing are here for the long term, regardless of the efficacy of vaccines. White House adviser Anthony Fauci last month stated that face coverings may be required until 2022, declaring that “there are things, even if you're vaccinated, that you're not going to be able to do in society.”

The World Health Organization declared last month that “there are still critical unknowns regarding the efficacy of vaccination in reducing transmission,” in a statement advising against the introduction of so-called ‘vaccine passports’ for air travel. This advice is set to be revised in May, and the latest findings from the UK and Israel could bolster the argument for proof of vaccination as a prerequisite for international travel.

Devi Sridhar, a professor of public health at Edinburgh University, predicted that the UK study will pave the way for “aviation & international mobility [safely opening] up with testing & vaccine passports,” but added that doing so would raise “major ethical issues.”