Global spreadThe first Covid-19 case outside China was recorded in Thailand on 13 January 2020. The WHO concludes that studies are urgently needed to investigate such instances and assess their significance for transmission of Covid-19. The study found that antibody responses may start to decline 20 to 30 days after Covid-19 symptoms emerge. The study that was published in the medical journal Lancet suggests that a so-called herd immunity to Covid-19 is "unachievable,". Since early on in the pandemic, the World Health Organization had warned that people who catch Covid-19 do not necessarily develop immunity.

Source: Daily Nation July 23, 2020 17:15 UTC