Case Report Adds To Evidence That Acute Pancreatitis May Be 'Rare Side Effect Of The Influenza Vaccine'

A case report of acute pancreatitis published in the International Journal of Surgery reportedly adds to a body of evidence suggesting that the condition could be a rare side effect of the influenza vaccine. Association between acute pancreatitis and the influenza vaccine is not well documented in medical literature. Any review of a link between acute pancreatitis and the flu vaccine yields only a handful of case reports.

Yet, a case report of a 70-year-old man admitted to the High Dependency Unit (HDU) at The Royal Bournemouth Hospital in Bournemouth, UK, reportedly adds to the existing evidence suggesting that acute pancreatitis could actually be among the rare side effects of the annual influenza vaccine. The author also said that existing case reports raise important questions concerning how pancreatitis cases with no known cause are investigated and documented.

Existing reports include a case report from the Journal of Hospital Medicine that also linked acute pancreatitis to the flu vaccine after an elderly woman developed the condition within a close time period of flu vaccination on separate years.

"We believe that our patient had pancreatitis as a response to the influenza vaccine she got, given the temporal relationship between injection of the vaccine and her illness. She had no history of gallstones and no history of alcohol use. She was also apparently healthy prior to getting her flu shot. Seven years earlier she had a similar episode which resolved with conservative measures. At that time her pancreatitis was deemed to have been due to her hydrochlorothiazide. The two episodes of pancreatitis in our patient followed the vaccinations too closely to be explained by chance alone."
Possible link between acute pancreatitis and the flu vaccine.

"The link with different vaccines is more established," the author of the Bournemouth case report published in the International Journal of Surgery stated.

See, several reports of vaccine-induced pancreatitis are documented following vaccination against hepatitis A, according to a report published in CMAJ, the medical journal of the Canadian Medical Association. Those authors meant to alert doctors that development of severe necrotizing pancreatitis is possible after vaccination. That report indicated there was established evidence linking both hepatitis vaccinations with acute or necrotizing pancreatitis. Additionally, a paper published in the BMJ indicated that there is documented evidence of a link between acute pancreatitis and MMR vaccination, chicken pox vaccination, hepatitis A vaccination, and typhoid and cholera vaccination.

Now, the case study from Bournemouth concluded that existing case reports do suggest a link between acute pancreatitis and the flu vaccine in particular. The Royal Bournemouth Hospital case study author said that the mechanism behind this link remains unclear. However, the report published by the Canadian Medical Association theorized that the mechanism could be autoimmune-related. A similar case study published in the European Journal of Medical Research that looked at a 23-year-old male who developed the condition after hepatitis A vaccination also theorized that mediators of allergic reactions might be induced by antigens in some vaccines, thereby triggering acute pancreatitis.

These cases are extremely rare, according to medical documentation. Meanwhile, alcohol consumption and gallstones are among the most common triggers for the condition. Viruses like measles, mumps, Coxsackie B, Epstein–Barr, hepatitis A, hepatitis B, and hepatitis E are also known to cause acute pancreatitis. The case reports of acute pancreatitis in association with influenza vaccination, these authors specify, should serve to make physicians alert to this possible link if they are presented with a case of pancreatitis that seems to have no cause. Doctors investigating idiopathic pancreatitis, they suggest, should inquire about recent flu vaccination, though the case studies are extremely rare in incidence.