A new study has hinted at the reason why the Delta variant remains so rampant even among populations with high vaccination rates.
The Imperial College London study showed that the highly transmissible strain of Covid is spreading from those who are vaccinated, to unvaccinated members of the same household.
Researchers insist that this does not change the argument for getting your vaccine and that a dose remains the best way of reducing serious illness from Covid-19.
They also said booster shots were required because infections were mainly found in those who were either unvaccinated or who received their dose long ago.
Speaking about the findings, Dr. Anika Singanayagam, co-lead author of the study said: "By carrying out repeated and frequent sampling from contacts of Covid-19 cases, we found that vaccinated people can contract and pass on an infection within households, including to vaccinated household members.
"Our findings provide important insights into... why the Delta variant is continuing to cause high Covid-19 case numbers around the world, even in countries with high vaccination rates."
More than 620 people took part in the study, where it was found that of 205 household contacts of people with Delta Covid-19 infection, 38% of household contacts who were unvaccinated went on to test positive, compared to 25% of vaccinated contacts.
Researchers found evidence of waning immunity in some participants after finding that vaccinated contacts who tested positive for Covid-19 on average had received their shots longer ago than those who tested negative.
These findings come after Dr Tony Holohan revealed vaccinations were “not performing as well as hoped” in reducing the transmission of Covid-19.
The Chief Medical Officer said Ireland’s high vaccination rate has prevented many hospital admissions, as well as hundreds of ICU admissions and deaths.
However, Ireland’s incidence of Covid-19 is still increasing at a concerning rate, while the seven-day moving average now stands at 2,043 up from 1,138 just three weeks ago.
He said: “Unfortunately, in crude terms, the vaccinations have probably done a little better than we might have hoped in terms of preventing severe infection.
“They have performed and held up their performance really well in protecting people from the severe effects of the disease.
“In truth they are probably not performing as well as we might have hoped in terms of preventing transmission.
“There is an impact on transmission by and to people who are vaccinated, but it’s not as great as we might like.
“The suppression that we’re seeing (from vaccination)… unfortunately, it’s just not quite enough on its own to suppress the transmission of the virus that has a natural transmission capability as high as Delta.
“This is a really highly transmissible virus.”
