DUBAI, United Arab Emirates — The United Arab Emirates and Bahrain are offering a booster shot of the Chinese-developed Sinopharm vaccine to residents and citizens who have already had two doses, the countries’ medical authorities said... ...The announcements come amid questions over Sinopharm’s efficacy and reports of Covid-19 reinfections among people who have received their two doses of the shot... ...In a national case that’s raised more concerns, the Seychelles — the most highly-vaccinated country in the world, with roughly 60% of those vaccinated having received Sinopharm — is seeing a new surge of Covid cases among vaccinated residents. Its...