AstraZeneca vaccine drops 3 percentage points in effectiveness rate

The makers of the Covid-19 AstraZeneca vaccine have dropped its effectiveness rate by 3 percent. The revised rate comes after an independent panel of experts appointed to supervise the trial expressed concern that AstraZeneca had failed to include updated data in its initially released figure. The US National Institutes of Health then issued a rare statement asking AstraZeneca to work with the panel to issue a new press release.

Now, the British-Swedish company says the vaccine is 76% effective at preventing any kind of symptomatic Covid, falling from the 79% that was reported in previous trials. It says it remains 100% effective against severe forms of the Covid virus.

The new figure is based on 190 people who fell sick among 32,449 trial participants across the United States, Peru and Chile, 2/3 of whom received the vaccine while the rest received a placebo. The previous figure was based on 141 cases, with the company adding that there are 14 more probable cases of Covid that are waiting to be adjudicated in the new figures, which could affect the rate positively or negatively by a few percentage points.

AstraZeneca was an early frontrunner in the global race to develop a Covid vaccine, with the United States ordering 300 million doses. But the US became less confident after several communication errors, resulting in the authorisation of other vaccines by Pfizer, Johnson & Johnson, and Moderna.

Recently, several European countries, as well as Thailand, halted the rollout of the vaccine over potential blood clot risks before later resuming its use. The European Medicines Agency responded to the concerns by deeming the vaccine safe and said it was not associated with blood clotting generally, but noted that it could not rule out a link to 2 highly rare forms of clotting. The agency then suggested that a warning label should be put on the vaccine packaging.

Meanwhile, the southern resort islands of Phuket and Koh Samui have made requests to the Public Health Ministry for enough doses of the AstraZeneca vaccine to inoculate a majority of the islands’ residents in anticipation of an early return to some semblance of tourism. Both holiday islands have a high reliance on tourist dollars. Private businesses in Phuket have made a formal request for 900,000 doses of the AstraZeneca vaccine to the Public Health Minister.

SOURCE: Bangkok Post