The technology behind Covid jabs

The drop is even greater in those vaccinated with AstraZeneca or Sinovac, a Chinese jab authorised in about 50 countries.

A booster seems to reignite antibody immunity with both Pfizer and Moderna announcing positive results from recent tests.

The catch is that nobody knows how long this boost lasts.

For Novavax, even less is known about its efficacy against variants since it was in clinical trials when the Alpha and Beta variants still dominated.

But this does not mean vaccines are useless against Omicron: the body has a secondary immune defence called T-cell response, which fights the virus by attacking infected cells.

This secondary response is particularly important in preventing severe forms of illness.

A recent study from South Africa showed Pfizer/BioNTech to remain effective at preventing severe Covid from Omicron even after just two shots.

Pfizer and Moderna have both said they are working on Omicron-specific jabs, but it is not clear whether they will be needed.

UNSETTLED YOUNGSTER DEBATE

The EU has followed the US and Israel in authorising jabs for children aged five to 11.

Children in the EU and US are allowed Pfizer/BioNTech at a third of the strength of an adult dose.

Comments are closed.