Reply letter to “safety of SARS-Cov-2 vaccines administration for adult patients with hereditary fructose intolerance”

ABSTRACT

In the letter, Urro et al. performed a search on the sucrose, fructose and sorbitol content in the approved Sars-Cov-2 vaccines and they concluded that these vaccines can be safely administered in adults affected by Hereditary fructose intolerance.

The Pfizer-BioNTech COVID-19 Vaccine is currently approved for use in adolescents ≥ 12 years and the Moderna COVID-19 vaccine is close to approval for use in children over 12 years of age. Furthermore, both vaccines have initiated clinical trials that will include infant as young as 6 months. Therefore, we considerate important to analyze the safely administration of this two vaccines in children with Hereditary fructose intolerance.

KEYWORDS:

• SARS-Cov 2; vaccine; Hereditary fructose intolerance; children; sucrose

Reply Letter

We Appreciate The Interesting Letter To The Editor Written By Urro Et Al¹ Titled Safety Of Sars-Cov-2 Vaccines Administration For Adult Patients With Hereditary Fructose Intolerance (HFI) (OMIM 229600).

Urro Et Al¹ Performed A Search On The Sucrose, Fructose And Sorbitol Content In The Approved Sars-Cov-2 Vaccines From The Summary Of Product Characteristics And The Fact Sheet For Healthcare Providers. They Found That The Content Of Sucrose For Each Dose Of Pfizer-Biontech COVID-19 Vaccine, Moderna COVID-19 Vaccine And Vaxzevria Vaccine Is 6 Mg, 43.5 mg And 30 Mg Respectively. Janssen COVID-19 Vaccine Is The Only One That Contains As Sugar Cyclodextrin Instead Of Sucrose. No Vaccine Contains Fructose Or Sorbitol. Urro Et Al¹ Mentioned That, At That Moment Sars-Cov-2 Vaccines Had Not Received Use Authorization For Pediatric Patients. However, The Pfizer-Biontech COVID-19 Vaccine Is Currently Approved For Use In Adolescents 12 Years And Older.^2–4 The Moderna COVID-19 Vaccine Is Close To Approval For Use In Children Over 12 Years Of Age.^4,5 Furthermore, Both Vaccines Have Initiated Clinical Trials That Will Include Infant As Young As 6 Months.⁵

We Thought That The Inclusion Of Adolescent And Children, Including Pediatric Patients With HFI, In The SARS-Cov 2 Vaccine Roll-Out Is Important To Limit Community Transmission And To Prevent Severe Complications Of Pediatric SARS-Cov 2 Infection. For These Reasons, We Considerate Important To Analyze The Safety Administration Of These Two Vaccines In Children With HFI.

The Content Of Sucrose For Each Dose Of Pfizer-Biontech COVID-19 Vaccine And Moderna COVID-19 Vaccine Is 6 Mg And 43.5 mg Respectively. According To A Recommendation Of The Instituto Superiore Di Sanità Of Italy,⁶ That Consider A Limit Of 2.4 Mg/Kg/Dose As A Safe Threshold For Oral And Parenteral Route For HFI Patients, If Pfizer-Biontech COVID-19 Vaccine Would Be Approved For Use In Children, It Could Be Safely Administered In HFI Infants. However, Moderna COVID-19 Vaccine Would Only Be Safely Administered At A Weight Above 18.2 Kg. This Weight Is Achieved Around 4.8 Years Old (50Th Percentile Of Weight For Age, According To The WHO Multicentre Study Growth, 2006). The Weight Of 18.2 Kg Corresponds To A 97Th Percentile Of Weight- For- Age At 3 Years (WHO Multicentre Study Growth, 2006). This Implies That, If Moderna COVID-19 Vaccine Would Be Approved For The Pediatric Age, It Could Not Be Safely Given In Children ≤ 3 Years Of Age. We Must Take Into Account That These Children Are Especially Vulnerable Due To The Difficulty Of Complying With The Contagion Prevention Measures.

In Conclusion, According To Instituto Superiore Di Sanità Of Italy Recommendation,⁶ If Pfizer-Biontech COVID-19 And Moderna COVID 19 Vaccines Would Be Approved For Use In Children, Only Pfizer-Biontech COVID-19 Vaccine Could Be Safely Administered In All Patients Affected By HFI. Nevertheless, Evaluating The Safety Of Each Dose Of Modern COVID-19 Vaccine According To The Patient’s Weight Would Be Necessary, Especially In HFI Children ≤ 3 Years Of Age, Because Their Weight Probably Is Not Above 18.2 Kg (Limit Of 2.4 Mg/Kg/Dose).

Disclosure of potential conflicts of interest

The authors report no conflict of interest.