BERLIN -- Benedikt Richter, a 40-year-old teacher in the southwest German city of Kaiserslautern, long held out against getting vaccinated against COVID-19. He felt uneasy about the novelty of the mRNA technology used in two of the most commonly administered shots.

It did not help that his sister-in-law was hospitalised with heart muscle inflammation a day after receiving her second shot, which doctors officially linked to her vaccine, Richter said. Regulators have acknowledged such conditions as a rare and mostly mild side-effect.

But when the European Union in December approved the use of the Novavax vaccine Nuxavoxid, which deploys a long-established protein-based technology, he became interested.

"I have done my research and I have a slightly better feeling about it," said the father of two.

Data unearthed by Reuters suggests the new two-dose vaccine, recommended in Germany for basic immunisation for people over 18, is already going some way to convince more of the as-yet unvaccinated to get a shot.

Some federal states have opened waiting lists to receive Novavax shots. In Rhineland-Palatinate where Richter lives, for example, more than 14,300 people have put down their names. A private Berlin vaccination centre told Reuters they had around 3,000 people registered.

"The number is gigantic. We're overwhelmed ourselves by how many people have signed up," said Daniel Termann, a doctor at the Historic Factory vaccination centre in Berlin.

The recombinant protein technology behind the Novavax shot has been in use since the mid-1980s and is now a standard tool to fight hepatitis B, the human papillomavirus behind cervical cancer, and bacteria that cause meningitis.

A recent survey by researchers at the University of Erfurt with 1,000 participants found that even though unvaccinated Germans had more confidence in traditional vaccines than in mRNA vaccines, trust generally was still low.