To the Editor:
After initial reports of anaphylaxis to the messenger RNA (mRNA)
COVID-19 vaccines, the Centers for Disease Control and Prevention (CDC)
put forth guidance stating that patients with a history of anaphylaxis
to vaccine components like polyethylene glycol (PEG) should not receive
the mRNA COVID-19 vaccines.1 To address this clinical
challenge and decrease vaccine hesitancy, we published an approach to
guide COVID-19 vaccination in high-risk allergy
individuals.2-4 While the etiology of anaphylaxis to
mRNA COVID-19 vaccines remains unclear, PEG continues to be an important
focus.5 Paclitaxel contains polyoxyl-35 castor oil
–a PEG derivative and the excipient in Pfizer-BioNTech and Moderna
COVID-19 vaccines– and docetaxel contains polysorbate 80 –the
excipient in Janssen COVID-19 vaccine. Given this, we sought to assess
the utility of pre-vaccine excipient skin testing (ST), risk
stratification and COVID-19 vaccine tolerability in oncology patients
with a history of paclitaxel or docetaxel hypersensitivity reaction
(HSR).
We included consecutive paclitaxel or docetaxel HSR patients referred to
allergy/immunology for evaluation prior to COVID-19 vaccination.
Evaluation included clinical risk assessment and excipient ST as
previously described.2,4 Clinical details were
obtained by electronic health record (EHR) review. COVID-19 vaccine
tolerance was determined by an allergy/immunology physician (AB) using
EHR review, phone call, and/or e-mail. This study was approved by the
Massachusetts General Brigham Institutional Review Board and deemed
minimal risk.
Between December 30, 2020 and April 2, 2021, 21 patients with paclitaxel
(n=17) or docetaxel (n=4) HSR were referred (Table 1 ). Most
were female (n=20, 95%) and white (n=20, 95%). Approximately half of
HSRs occurred in the past 4 years (n=11, 52%) and 6 (29%) HSRs were
anaphylactic. 20 patients (95%) had negative excipient ST. One
paclitaxel HSR patient had positive ST (methyl-prednisolone acetate
PEG3350, 0.4 mg/mL intradermal) and tolerated the Janssen COVID-19
vaccine (Table 2 ). All patients completed COVID-19 vaccination
with no reaction (n=19, 90%) or with mild symptoms treated with
antihistamines alone (n=2, 10%). Of 17 patients with history of
paclitaxel HSR, 12 (71%) received an mRNA COVID-19 vaccine and none had
a reaction.
This case series of 21 patients suggests that patients with paclitaxel
(containing the excipient polyoxyl-35 castor oil/PEG derivative) or
docetaxel (containing the excipient polysorbate 80) HSRs tolerate
COVID-19 vaccination. While 2 patients (10%) developed reactions after
COVID-19 vaccination, symptoms resolved with antihistamines alone. The
reactions do not appear related to the patient’s specific excipient
allergy history (e.g., docetaxel HSR patient developed reaction with
mRNA vaccine) and in fact, no reactions occurred in paclitaxel HSR
patients that received an mRNA COVID-19 vaccine. It remains unclear if
the paclitaxel HSR patient with positive intradermal PEG ST would have
tolerated mRNA COVID-19 vaccination, but experience to date indicates
that positive PEG intradermal ST does not predict reactions to mRNA
COVID-19 vaccines.4
CDC guidance advises patients with PEG allergy to proceed with Janssen
COVID-19 vaccination while patients with polysorbate 80 allergy can
proceed with mRNA COVID-19 vaccines.1 However, if both
COVID-19 vaccine platforms are not routinely accessible,
allergy/immunology consultation may be useful for allergy risk
assessment and vaccine guidance. Furthermore, if mRNA COVID-19 vaccines
are proven optimal for oncology patients, allergy assessment and limited
excipient ST (e.g. Miralax, PEG- 3350)2,4 can provide
reassurance prior to mRNA COVID-19 vaccination in patients with HSR to
chemotherapeutics containing PEG. We continue to advise 30-minute
monitoring post COVID-19 vaccination for all patients with any history
of anaphylaxis per CDC guidance.1 This study was
limited by its small sample from a single institution and retrospective
study design.
The role of excipient ST prior to COVID-19 vaccination appears limited
and patients largely tolerated COVID-19 vaccination despite paclitaxel
or docetaxel HSR. Reassuringly, COVID-19 vaccine anaphylaxis remains
rare.