Experts: Flu-like symptoms after vaccination known

Pune: Experts stressed that all flu-like symptoms — fever, headache, body ache, tiredness and chills — were adverse reactions or side-effects of a vaccine if they happened within 48 hours of the vaccination and they resolved on their own.

They explained that not all side-effects were adverse events (AE) and not all adverse events were related to the vaccine. The terms should be used very cautiously, said experts.

“‘After this, therefore because of this’, is a very common fallacy in human logic. Not every Y that follows X is caused by X. It could be just coincidental,” said vaccine scientist Prasad Kulkarni.

There may be AEs that are not related to the vaccine. “These unrelated events may occur either due to pre-existing known or unknown medical condition of the patient or due to the causes which have nothing to do with the vaccine,” he said.

In all clinical trials across the globe, AEs occur. In fact, one of the purposes of clinical trials is to find out the AEs caused by the drug under trial.

“This helps to define the safety profile of the vaccine during the trial phase. Investigating every instance of AE also helps find out which AEs are vaccine-related. Hence, during immunisation of kids, parents are informed about the common symptoms that the kids will be exhibiting,” said senior paediatrician Sharad Agarkhedkar.

To give an example, if somebody gets a vaccine and meets with an accident, then it becomes an AE, but it is obviously not related. If a child gets a pentavalent vaccine and gets fever on the next day, it is also an AE and it is related to the vaccine, he added.

“Hence, when authorities put down everything that happens, including fever to accident, under AEFI (adverse event following immunisation), we need to know that not every instance is vaccine related,” Agarkhedkar said.

“All medicinal products, including vaccines, have adverse events and adverse drug reactions. But the benefits they provide to mankind are far more than these risks of AEs and ADRs, and hence they are licensed by the regulator,” said Sanjay Patil, the chairman of the Indian Medical Association’s Hospital Board of India, Pune chapter.