Japan is set to miss its goal of administering COVID-19 booster shots to nearly 30% of its residents by the end of the month, even if the rollout were to double from its recent pace of around 1 million shots per day.

Though domestic COVID-19 cases have apparently peaked, experts are increasingly worried that the low booster coverage could prolong the nation's omicron-driven sixth wave, which has seen cases and deaths hit record levels.

Japan's booster rollout has lagged far behind over developed countries.