
Initially, these individuals received a vaccination certificate that stated that they had received “3/3" doses, essentially as if they had received two doses and a booster shot.
However, this was recently changed on the basis of an EU recommendation.
The new certificates for people vaccinated with one dose of the J&J vaccine as well as an additional mRNA booster now read “2/1", which is still accepted as “fully vaccinated” in Luxembourg.

This generally also applies to other EU member states but not every country has already implemented the new provisions. For this reason, the National Health Directorate recommends that affected individuals still carry their old “3/3" certificate with them while travelling.
However, this does not apply to Germany. In Luxembourg’s neighbouring country, people who have received a single dose of J&J + an mRNA booster are as of 15 January 2022 no longer considered to have received a booster shot.
Other European countries, including Luxembourg through its High Council for Infectious Diseases, are considering a similar approach. However, official decisions have so far not been reached.