Chinese drug giant Sinopharm's COVID-19 vaccine trial in Peru has hit a roadblock after one of the volunteers had an adverse side-effect. The South American country's National Institute of Health (NIH) has suspended the clinical trial momentarily as experts dig in to understand the cause.

Sinopharm's trial was scheduled to be completed by December 13 after testing nearly 12,000 volunteers but with the unexpected setback, it remains to be seen if Peru continues with the trial or approves the vaccine. As for the trial volunteer, the individual developed neurological symptoms including difficulty in moving the arms. According to Peru's NIH, the symptoms were of a condition called Guillain-Barre syndrome.

"Several days ago, we signaled, as we are required, to the regulatory authorities that one of our participants (in trials) presented neurological symptoms which could correspond to a condition called Guillain-Barre syndrome," chief researcher German Malaga told the local press.

Sinopharm
Sinopharm's COVID-19 vaccine has been approved by Bahrain and the UAE besides China (representational image) Sinopharm website

Guillain-Barre Syndrome

Guillain-Barre syndrome (GBS) is an autoimmune condition in which the body's immune response attacks healthy nerve cells. It leads to nerve damage causing weakness, numbness and tingling while in severe cases, it causes paralysis. As for Sinopharm's vaccine, it is still unknown if the vaccine jab or any underlying condition triggered the trial volunteer's illness.

While GBS is a rare disorder, it is not the first time that a vaccine candidate has led to the disorder. In 1976, during the mass swine flu vaccination program, GBS was noticed in around 450 people who received the shots. The vaccine drive was halted but the concerns grew over the years.

While this is the first time that a COVID-19 vaccine candidate has supposedly caused GBS symptoms, in other vaccine trials, a few have developed neurological problems. In September, a trial volunteer in AstraZeneca's COVID-19 vaccine candidate developed neurological issues and the trial had to be paused. In India, another volunteer developed a severe neurological condition. But the Serum Institute of India, behind the clinical trials, rejected the claims that the vaccine had anything to do with the patient's condition. Other vaccine candidates have had mild side-effects including fever, chills, swelling and pain at the injection site.

Coronavirus vaccine
Peru tested around 12,000 volunteers with Sinopharm's COVID-19 vaccine and supposed to buy 20 million doses (representational image) Pixabay

Sinopharm's Vaccine Candidate

So far, the Sinopharm vaccine has been given to nearly 60,000 trial participants all over the world but this is the first time that anyone has reported any adverse side-effects. The vaccine candidate which claims to have 86 percent efficacy has been approved by Bahrain and the United Arab Emirates besides China.

In Many South American and Southeast Asian countries besides Middle Eastern nations, Sinopharm's vaccine will be sold. However, with the pause in trial, the Peruvian government is unlikely to begin vaccinating people before mid-2021. The country was supposed to buy 20 million doses of Sinopharm vaccine to inoculate its population. Peru is one of the worst-hit countries in South America with nearly 1 million positive cases of COVID-19 with over 36,000 dead.

Indonesia has also ordered around 74 million vaccine doses from the Chinese company. However, with the adverse side-effect, it remains to be seen if countries that have approved the candidate go forward with inoculating their citizens.