File photo. One Covid-19 vaccine has its trials on hold while medics investigate a possible adverse reaction in a patient in England.

Oxford, England–AstraZeneca has put its COVID-19 vaccine trial on hold due to a possible serious adverse reaction in a participant in the U.K.

The Phase 3 study, which is being performed by AstraZeneca in partnership with the University of Oxford.

Rebecca Robbins of the Web site Stat.com reported receiving two statements from the company in a Tweet, saying that it had voluntarily put the study on hold.


This announcement caused considerable consternation yesterday, and the company was quick to follow up with clarification after a person familiar with the situation told The New York Times that the participant had been enrolled in a Phase 2/3 trial based in the United Kingdom.

 

 

It is expected that the company’s medical team will now thoroughly investigate the alleged adverse reaction to see if it was caused by the vaccine, or by some other medical condition.

The AstraZeneca vaccine has received millions of orders for its $4 per dose vaccine, and it would be a major blow to the company if the vaccine was deemed to be too dangerous to use. However halts in testing are not uncommon, and this could easily prove to be a false alarm.

Meanwhile, in South America, President Nicolás Maduro has announced that Russia’s locally licensed coronavirus vaccine will be delivered to Venezuela this month for clinical trials.

In a televised address on Tuesday, the president said “other vaccines” would also arrive in October, although he did not specify which ones.

According to official government figures, Venezuela has more than 55,000 confirmed cases and 444 Covid-related deaths, much lower than its neighbours Colombia and Brazil, which have almost 680,000 and 4.1m cases respectively.

However, health workers have claimed that the real figures are much higher and that a lack of testing is to blame for the low official numbers.

Doctors United for Venezuela called on government spokespeople “to adjust their figures to reality”.

Reuters news agency also reports that Russia will sell 32m doses of its ‘Sputnik-V’ inoculation to Mexico.

Sputnik-V has been licensed for use in Russia after two months of small-scale human tests.

Nearly 180 vaccine candidates are being tested around the world, according to the World Health Organization (WHO). The UN body has said none of the candidates have so far demonstrated a “clear signal” of efficacy at the level of at least 50% sought by the WHO.

Editor’s note: This report contains information from the BBC and other sources.