An even more contagious variant spreading in Europe?

The Delta variant of Sars-Cov-2, estimated to be 60% more contagious, is already dominant in the majority of cases in Portugal, just as it is in Luxembourg. It has jumped from 4% of cases in May to a whopping 55.6% in June.

Read more: Delta variant dominates cases in Luxembourg with 59.4 percent

Among the 766 cases sequenced with the Delta variant, 46 were "Delta Plus", according to the Portuguese National Health Institute 'Doutor Ricardo Jorge'. Experts have confirmed very limited local transmission, with the variant making up around 2.3% of new cases.

Portugal has reported a total of 347 cases of the Delta Plus variant, which has since been split into two lineages: AY.1 and AY.2.

AY.1 is the one most common in Portugal, which reports 46 cases out of the 206 cases worldwide. These numbers have doubled in a week. This means that Portugal has now overtaken the UK in numbers detected of the variant, and is the first European country to have confirmed local transmission.

Preliminary results from in vitro analyses suggest a lower neutralising ability by antibodies from previous Covid waves, which could mean that non-vaccinated people are at higher risk of catching the virus, even if they were previously infected.

Are the vaccines still effective?

Regarding vaccines, they still offer strong protection against a severe illness, but lower protection against infection altogether, especially after only one jab.

According to British experts, a single dose of vaccine protects against symptomatic infection in 49% of cases for the Alpha variant, but only in 35% for the Delta variant. After two doses, it is estimated to be 89% for Alpha and 79% for Delta.

Vaccine effectiveness remains high for protection against hospitalisation: after one dose, it is estimated to be 78% for Alpha and 80% for Delta. After two doses, this increases to 93% for Alpha and 96% for Delta.

The main concern of scientists is that with the higher transmissibility, including among those already vaccinated, the total number of people who will catch it (and can thus develop a more severe case) will increase.

As far as the Delta variant goes, Public Health England estimates that this preliminary data is still reassuring, as vaccine protection is largely maintained.