Brussels, Jun 25 (IANS): Taking painkillers before a Covid-19 shot to prevent potential side effects is not advised, as it may impact the vaccines' efficacy, said the World Health Organization (WHO), the media reported.

However, one can take "paracetamol or other painkillers" to control side effects such as pain, fever, headache, or muscle aches post vaccination, said the global health body, the Euronews reported.

The WHO said this after several fake posts on social media orchestrated the need for taking antihistamines and other painkillers available over the counter, before getting the Covid shots to help relieve the potential side effects of the vaccine.

"Taking painkillers such as paracetamol before receiving the Covid-19 vaccine to prevent side effects is not recommended," a spokesperson was quoted as saying.

"This is because it is not known how painkillers may affect how well the vaccine works."

"However, you may take paracetamol or other painkillers if you do develop side effects such as pain, fever, headache, or muscle aches after vaccination."

The common side effects of the vaccine, such as arm soreness, headaches, or tiredness, are minor in most cases, the WHO added.

But while antihistamines can mitigate certain allergic reactions, they are not designed to prevent them.

Experts have advised against taking vaccines unless one develops side-effects.

But, "if you're already on any medication at all, you should check with your local doctor, as some people may be advised to keep taking antihistamines for rashes and other allergic reactions," Professor Luke O'Neill, Chair of Biochemistry at Trinity College Dublin, was quoted as saying to Euronews.

"But there's no reason to start taking painkillers ahead of the vaccine, just in case they might limit vaccine efficacy," he added.