Mossialos: Delta Variant Means More Vaccinations Are Needed for Herd Immunity

ATHENS — The Delta variant of Covid-19 has increased the percentage of the population that needs to be vaccinated or otherwise immune to stop the virus spreading, Professor of Health Policy at London School of Economics and Social Science Elias Mossialos said in a social media post on Friday.

He said that a 70-75 pct immunity rate – either through vaccination or after infection – will no longer be sufficient and its estimated that this must now increase to more than 82 pct of adults to protect the community. According to Mossialos, those at risk were mainly adults that have not been vaccinated, children (who have also not been vaccinated but have milder symptoms) and some 4-8 pct of people who can become seriously ill due to the Delta variant, in spite of being vaccinated.

According to Mossialos, the vaccines are less effective against the Delta variant, which causes serious illness in 4-8 pct of vaccinated individuals and milder illness in 12-33 pct. The Delta variant is much more easily transmitted, he added, but the data so far do not indicate that it's more lethal.

Asked why the number of cases has increased in countries like the UK and Israel, where significant numbers have been vaccinated, Mossialos said that vaccination rates in both countries remained below 60 pct of over-16s. Adding the 10-15 pct of those that have immunity because they have already had Covid raises this to 70-75 pct with immunity but this appears to be insufficient to control the Delta mutation.

While the UK was the country with the most new cases, he pointed out, it had the smallest number of serious cases, which meant that vaccines work.


ATHENS - A young woman who became the first patient in Greece to receive a liver transplant from a living donor, her father, was released from hospital on Friday.

Top Stories


A pregnant woman was driving in the HOV lane near Dallas.

General News

NEW YORK – Meropi Kyriacou, the new Principal of The Cathedral School in Manhattan, was honored as The National Herald’s Educator of the Year.


THE HAGUE (AP) — The United Nations’ highest court on Monday wrapped up historic proceedings into the legality of Israel’s 57-year occupation of lands sought by Palestinians for a future state, with most voices at the hearing arguing against the Israeli government.

NEW YORK (AP) — Donald Trump has appealed his $454 million New York civil fraud judgment, challenging a judge’s finding that Trump lied about his wealth as he grew the real estate empire that launched him to stardom and the presidency.

BUDAPEST, Hungary (AP) — Hungary’s parliament voted Monday to ratify Sweden's bid to join NATO, bringing an end to more than 18 months of delays that have frustrated the alliance as it seeks to expand in response to Russia's war in Ukraine.

NEW YORK (AP) — New York City is marking the anniversary of the 1993 bombing at the old World Trade Center that blew apart a van parked in an underground garage, killing six people and injured more than 1,000.

Enter your email address to subscribe

Provide your email address to subscribe. For e.g. [email protected]

You may unsubscribe at any time using the link in our newsletter.