BUENOS AIRES (Reuters) -Argentina began to vaccinate its citizens against the coronavirus on Tuesday using 300,000 doses of the Russian Sputnik V vaccine delivered last week, the government said. Latin America’s third largest economy has been hard hit by COVID-19, logging nearly 1.6 million cases of the disease and 42,868 deaths. Fears of a second wave are growing. Officials said front-line health workers would be the first to be vaccinated, followed members of the security forces, teachers, the elderly and other high-risk groups. Argentina became the third country to approve the Sputnik V vaccine, after Russia and Belarus. Critics both in Argentina and abroad have questioned the vaccine’s efficacy, side effects and the transparency of its trial results. Russia says those criticisms are unfounded. “You have to be afraid of the disease, not the vaccine,” Argentine Health Minister Ginés González García told reporters on Tuesday. Reuters reported on Monday that the vaccine sent to Argentina - Russia’s first major international shipment - consisted only of the first dose of the two-shot vaccine, which is easier to make than the second dose. Russian and Argentine officials did not immediately comment on when the second dose might arrive. President Vladimir Putin has referred to a single-component option as a “light-vaccine”, which he said would provide less protection than the two components, but “will still reach 85%” effectiveness. Argentina has also approved the COVID-19 vaccine manufactured by Pfizer and BioNTech.