Italy prepares for an 18th weekend of demonstrations against the country’s health pass.

Demonstrators prepared to gather in Milan and Rome on Saturday evening to protest Italy’s coronavirus health pass on the 18th consecutive weekend of such rallies. Organizers considered a strong showing necessaryto prove that they were a force to be reckoned with.

Police officers were out in force to protect shops and preventviolence. Store owners have lamented that the protests disrupt business, especially as Christmas shopping is ramping up.

After an initial large rally in Rome in October that was hijacked by violent neofascists and a burst of activity in Trieste, a northeastern port city, the demonstrations have diminished. After suffering through one of the world’s worst outbreaks early in the pandemic, most of the Italian public has embraced vaccination. And while the country is experiencing part of the Europe-wide surge in cases, the bump in its caseload has been relatively small.

Roberto Burioni, a leading virologist at San Raffaele University in Milan, attributed Italy’s success in keeping down its Covid numbers partly to its aggressive vaccination campaign — more than 73 percent of the population is fully inoculated — and partly to its early intervention with the health pass. Requiring that certificate, known as a Green Pass, has allowed Italy to avoid more draconian measures, he said, such as the nationwide lockdown being imposed in Austria starting next week.

Mr. Burioni also said the strict measures in the Green Pass, which is required for entry into bars and clubs, had perhaps motivated Italy’s younger people to get vaccinated.

“What is surprising is the rate of vaccination for people between 19 and 29,” he said, putting the rate at nearly 84 percent. “It is very high.”

As Italian officials continued to urge people to get inoculated against the virus, the government on Friday reported success in delivering third vaccine doses to people, with 160,000 doses administered in 24 hours. But roughly 6.7 million Italians over age 12 remain unvaccinated, in a country of just over 60 million people.

When the Green Pass was introduced last month, it was the toughest such measure in Europe, requiring the entire Italian work force tobe vaccinated, have recovered from the virus or have frequent negative tests to earn a paycheck.

The government has said that it has no plans to toughen up the pass. But some top ministers and many politicians in the country’s northern regions, which share border with Austria and other countries in which cases are soaring, are urging that the swab option be taken away, essentially mandating vaccinations.