Tonsillectomy – do they affect future immunity?

July 1st, 2018, Dr Chee L Khoo

I am sure you have been asked by parents of young patients about to undergo tonsillectomy +/- adenoidectomy whether the removal of the tonsils will affect future immunity since the tonsils and adenoids are integral to the body’s immune response. I have had those questions asked of me and the answer used to be “Of course not. We are just removing the excessive grown tonsils and as such, should not affect your child’s immunity”. Does tonsillectomy affect future immune related risks?

You will recall that the pharyngeal, palatine and lingual tonsils form the Waldeyer’s ring at the entrance to the respiratory and gastrointestinal tract providing early warning for inhaled or ingested pathogens. They protect us from pathogens directly and indirectly by modulating other immune responses to the invasion by these pathogens. Any disturbance or alteration of these pathways especially during the early formation years can have long term effects on adult health. So, does tonsillectomy +/- adenoidectomy affect affects this pathway development?

Tonsils and adenoids are often removed in early childhood age. There are suggestions from studies that tonsillectomy/adenoidectomy may increase risk of asthma, certain type of cancers, inflammatory bowel disease and premature acute myocardial infarctions but the data is not robust.

Data from the Danish Birth Registry were used to estimate the disease risk if tonsillectomy, adenoidectomy or both were performed in the first 9 years of life. The health of 1.2 million singletons born between 1979 and 1999 were evaluated in 2009 (i.e. up to 30 years follow up!). Risks of 28 diseases were considered. These included infections, allergies, circulatory, endocrine, neurological and autoimmune diseases. The study calculated the relative risks, absolute risks and number needed to treat to gain a balanced and realistic view on how surgery affects the disease risks up to 30 years of age.

What did they find?

Tonsillectomy is associated was associated with almost 3 times the relative risks of upper respiratory tract and 18.6% increase in absolute risks. 18.6% may not sound too bad but considering the prevalence of upper respiratory tract infections, the number to harm (NNH) is 5. This means we only need to perform 5 tonsillectomies to cause one additional URTI in these patients. And when you magnify this on a population basis, the impact on the overall population is considerable.

Adenoidectomy is associated with more than doubled the relative risk of chronic obstructive pulmonary disease (COPD) and nearly doubled the relative risks of URTI and conjunctivitis. Once again, this translate into significant NNH – URTI = 9, COPD = 349 and Conjunctivitis = 624.

Adenotonsillectomy is associated with 17% increase in relative risks of infectious diseases.

Did surgery achieve their outcomes?

The other side of the coin we need to consider is that tonsillectomy with or without adenoidectomy is often done to reduce the frequency of tonsillitis and sleep disorders. Yes, surgery did improve the relative risks of acute or chronic tonsillitis and sleep disorders but not sinusitis or otitis media in the short term. In fact, adenotonsillectomy was associated with more otitis media. In the longer term though, the risks of abnormal breathing, sinusitis and otitis media were either higher or the same.

Hang on a minute…

One of the major limitations of the study is the lack of data on parental smoking. It may be that children growing up in a smoked environment are more prone to recurrent URTIs leading to tonsil and adenoid hypertrophy necessitating surgery. These may be the same kids needing surgery and continue to have recurrent URTIs and COPD later on in life. Nonetheless, we need to consider the pros and cons of surgery and explore other alternatives to surgery.

Access the abstract here.


Sean G. Byars, PhD; Stephen C. Stearns, PhD; Jacobus J. Boomsma, PhD. Association of Long-Term Risk of Respiratory, Allergic, and Infectious Diseases With Removal of Adenoids and Tonsils in Childhood. JAMA Otolaryngology–Head & Neck Surgery Published online June 7, 2018