PERTH, Australia – The Australian government is recommending that Australians under 50 take the Pfizer Inc. COVID-19 vaccine due to the risk of rare blood clots associated with Astrazeneca plc’s COVID-19 vaccine (ChAdOx1-S). The move jeopardizes Australia’s vaccine rollout as it had planned for the majority of Australians to receive the Astrazeneca vaccine, which is being locally manufactured by CSL Ltd.

HONG KONG – In a surprisingly candid statement, the director of China’s Centers for Disease Control conceded that the efficacy of Chinese coronavirus vaccines is "not high" and may require improvements.

LONDON – The U.K. is moving on to the next phase of testing mixed dosing schedules for COVID-19 vaccines, launching a study in which it will assess the effect of using Moderna Inc. or Novavax Inc.’s products as the second dose in a heterologous prime boost trial.

The FDA and the CDC have jointly recommended a temporary pause in the further rollout of Johnson & Johnson Co.’s COVID-19 vaccine while they investigate six rare clotting cases in adults ages 18 to 48.

HONG KONG – In a surprisingly candid statement, the director of China’s Centers for Disease Control conceded that the efficacy of Chinese coronavirus vaccines is "not high" and may require improvements. George Gao, the director of China’s CDC, stated that Chinese vaccines “don’t have very high protection rates” at the National Vaccines and Health conference in the southwestern city of Chengdu on Saturday.

CAJICA, Colombia – Following the start of phase III trials for its COVID-19 vaccine, Soberana 02, Cuban researchers have started phase III trials for Abdala (CIGB-66), another vaccine candidate developed in the island country.

LONDON – The EMA has concluded that the rare cases of serious blood clots with low platelet counts seen after administration of Astrazeneca plc’s COVID-19 vaccine are caused by the vaccine, but said the benefits of its use continue to outweigh the risks. The possibility of cerebral venous sinus thrombosis and splanchnic vein thrombosis in the abdomen will now be listed as rare side effects and the EMA’s guidance to health care professionals will be updated.

If these top-line phase III results were a grade card for 12- to 15-year-olds, they would be on the honor roll: The Pfizer Inc.-Biontech SE COVID-19 vaccine is 100% effective for the age group and produced robust antibody responses. The new results play out against a backdrop of increased production and big revenue estimates.

As COVID-19 vaccinations continue to roll out, momentum builds with strong phase III data for what could become the fourth and fifth walls of defense in the U.S. With three vaccines already authorized, research reported in March offers hope for a second adenovirus vector vaccine candidate with Astrazeneca plc’s AZD-1222, as well as for the first protein subunit vaccine option with Novavax Inc.’s NVX-CoV2373.