Belgrade, Dec 6 : The overall number of COVID-19 cases in Serbia has increased to 213,843, as authorities try to expand capacities for the growing number of severe cases. The Ministry of Health confirmed on Saturday afternoon another 6,903 infections from testing 18,232 people in the past 24 hours. In the same period, 57 people died, raising the Covid-19 death toll in Serbia to 1,891, Xinhua news agency reported. Since Nov. 19 when Serbia crossed the threshold of 100,000 cases, the number of total cases has doubled. Hospitals across the country shelter 7,988 patients with coronavirus infections, 279 of whom are on ventilators. In addition to the numerous medical institutions, sport, concert and expo venues such as Belgrade Arena are also serving as temporary hospitals for Covid-19 patients. Besides prevention measures such as obligatory mask-wearing indoors and social distancing, starting from Friday, Serbia has been restricting working hours for most businesses on weekends as well as workdays. Mirsad Djerlek, state secretary at the Ministry of Health, said Friday that vaccination of the general population can be expected in the first quarter of 2021, while doctors, policemen and soldiers can expect it before the end of this year. As the world is struggling to contain the pandemic, countries including Germany, France, China, Russia, the United Kingdom and the United States are racing to find a vaccine. According to the website of the World Health Organization, as of November 26, there were 213 Covid-19 candidate vaccines being developed worldwide, and 49 of them were in clinical trials. So far two types of vaccines were submitted for testing here in Serbia -- the Sputnik V and the Pfizer-BioNTech vaccine. /IANS