WARSAW, Poland (AP) — The mayor of Poland's capital, Warsaw, said Friday he has COVID-19. Again.

Mayor Rafal Trzaskowski said on Twitter the virus seems to be “even more treacherous and contagious” then before and its symptoms are far from banal. Last year he was hospitalized due to a coronavirus infection.

He appealed to the Poles not to ignore the threat of potential reinfection. Trzaskowski, an opposition figure, also criticized Poland's right-wing government for having taken no preventive steps of late to counter new variants.

The Health Ministry estimates the level of immunity in this nation of 38 million is above 90% due to inoculations, more than 54 million jabs, and to the resilience of those who have recovered from the disease. Nationwide measures are to be introduced when the number of those hospitalized for COVID-19 reaches 5,000.

But experts are saying the new variant is highly contagious and steps against its spreading should be taken now. The number of new registered infections was almost 2,000 on Friday and two people have died, while a week ago it was just over 1,000 new cases and no deaths.

Follow all AP stories on the pandemic at https://apnews.com/hub/coronavirus-pandemic.