Ontarians eager to get their fourth COVID-19 vaccinations lined up outside clinics and waited in online queues on Thursday as the province opened access for the shots to all adults. As of 8 a.m., adults aged 18 to 59 who received their first booster at least five months prior could book their next shot through the province's online portal. Appointments were also available through pharmacies, public health unit booking systems and at walk-in clinics.