JERUSALEM, Oct 3 (Reuters) - Israel on Sunday piled pressure on its vaccinated citizens to get a booster shot by making only those who received their third dose of the COVID-19 vaccine eligible for a "green pass" allowing entry to restaurants, gyms and many other venues. Israel was an early adopter of Pfizer/BioNtech booster shots -- administering them to members of risk groups in July and by the end of August to anyone above the age of 12. Its campaign is being watched closely by other countries. The new green pass is being issued to those who received three shots or recently recovered from COVID-19, replacing a previous system that required just two shots. It raises the bar for what the government considers full immunization. Starting on Tuesday, store owners or event organizers will have to scan a customer"s digital barcode before allowing entry. There will be some exemptions, such as museums and libraries. About 37% of Israel"s 9.4 million population has received a booster shot. The number of COVID-19 patients hospitalised in serious condition has been dropping in recent days, as has the number of confirmed daily cases, which fell to below 4,000 after topping 10,000 last month.