LISBON, Nov 16 (Reuters) - Portuguese Prime Minister Antonio Costa said on Tuesday that authorities in one of the world"s most vaccinated nations may bring back some measures to stop the spread of COVID-19 in the run-up to the holiday season as infections soar across Europe. The number of new cases has been gradually rising over the past month in Portugal, reaching a two-month daily high of 1,816 infections on Saturday.The 14-day infection rate stood at 156 cases per 100,000 people on Monday, about double that in neighbouring Spain, which has a slightly lower share of its population fully vaccinated, but still well below over 500 in Germany and more than 900 in the Netherlands. "We must try to act now so we can reach the Christmas period with less fear," Costa told reporters on the sidelines of an event in central Portugal. "The later we act, the greater the risks." Government ministers are expected to meet health experts on Friday to evaluate the situation and only then will decide on which rules to impose. Costa said measures would be only applied when "strictly necessary". Around 86% of Portugal"s population of just over 10 million is fully vaccinated against COVID-19. It has reported around 1.1 million cases and 18,265 deaths since the pandemic began. The country faced its toughest battle against COVID-19 in January, forcing authorities to impose strict lockdown measures, that have since been lifted. Costa said the government was unlikely to bring back a lockdown and that the new measures would aim to "disturb people"s lives as little as possible". Mask-wearing is still required in public transport, shopping malls and large gatherings. The EU digital COVID-19 certificate is required to enter nightclubs and big events, as well as to travel.