Study examines systemic reaction rates with concurrent COVID-19 and flu vaccines

Current clinical guidelines in Canada state that COVID-19 vaccines may be administered without regard to timing of other vaccines in individuals five years of age or older. This means that COVID-19 vaccines may be given concurrently with (i.e., same day, at different injection sites) or at any time before or after non-COVID-19 vaccines (including live and non-live vaccines).1 Canadian guidelines also maintain that there are currently limited data on whether the reactogenicity of COVID-19 vaccines is increased with concurrent administration of other vaccines, although no specific safety concerns have been identified to date.1 Read: Physician and pharmacist team up to offer hair loss solutions The safety of simultaneous administration of COVID-19 and influenza vaccines has not been well described. To further examine this issue, a group of U.S. investigators recently examined the reactogenicity of giving a COVID-19 mRNA booster (Moderna or Pfizer–BioNTech) and influenza vaccine simultaneously versus a COVID-19 booster given alone. The retrospective cohort study involved self-reported vaccine data collected on days zero through seven after vaccination (from September 2021 to May 2022), through V-Safe, a voluntary smartphone-based monitoring system established by the U.S. Centers for Disease Control and Prevention. The main outcomes were local injection site reactions and systemic reactions (e.g., fatigue, headache, myalgia) and health impacts reported by V-Safe respondents in the week following COVID-19 mRNA booster vaccination. Adjusted odds ratios (aORs) were estimated for simultaneous administration compared with a COVID-19 booster dose alone, while controlling for sex, age and week of vaccination. The main results were: A total of 981,099 persons aged 12 years or older registered with V-Safe were included in the study. Simultaneous administration of a COVID-19 mRNA booster and seasonal influenza vaccine was reported by 92,023 (9.4%) V-Safe respondents (59.7% female, 39.4% male, 0.9% sex unknown). Local injection site reactions occurred with similar frequency when COVID-19 and influenza vaccines were administered simultaneously compared with COVID-19 vaccine given alone. In the week following vaccination, systemic reactions were reported by 36,144 of 61,390 (58.9%) respondents who simultaneously received Pfizer-BioNTech booster and influenza vaccine, and by 21,027 of 30,633 (68.6%) respondents who simultaneously received a Moderna booster and influenza vaccine. Respondents who simultaneously received influenza and Pfizer–BioNTech booster vaccines (aOR, 1.08; 95% CI, 1.06-1.10) or influenza and Moderna booster vaccines (aOR, 1.11; 95%CI, 1.08-1.14) were slightly more likely to report any systemic reaction in the week following simultaneous vaccination than respondents who received only a COVID-19 mRNA vaccine booster. Systemic reactions after simultaneous vaccination, or a COVID-19 mRNA booster alone, were usually mild and occurred most frequently on the day following vaccination. Fatigue, headache and myalgia were the most common systemic adverse effects. Respondents who simultaneously received influenza and Pfizer-BioNTech COVID-19 booster vaccines were not more likely to report a health impact (e.g., unable to perform normal daily activities, missed work or school) in the week following vaccination (aOR, 0.99; 95%CI, 0.97-1.02) than respondents who received a Pfizer–BioNTech COVID-19 booster alone. Respondents who simultaneously received influenza and Moderna COVID-19 booster vaccines were slightly more likely to report a health impact in the week following vaccination (aOR, 1.05; 95%CI, 1.02-1.08) than respondents who received a Moderna COVID-19 booster alone. The investigators concluded that simultaneous administration of an mRNA COVID-19 vaccine plus influenza vaccine led to a slightly higher rate of systemic adverse effects the following week compared to administration of an mRNA COVID-19 booster alone (an 8% increase with the Pfizer-BioNTech vaccine and an 11% increase with the Moderna vaccine). However, most systemic reactions were generally mild. A commentary accompanying the U.S. study points out that concomitant administration of a COVID-19 booster and the seasonal influenza vaccine could enhance uptake of both vaccines and promote efficiencies in currently overburdened healthcare settings. The results of this study support the development of public health campaigns to promote dual COVID-19 and influenza vaccination. Healthcare systems should be encouraged to develop routine and streamlined processes for co-administration of these vaccines.3 Read: How common are primary psycho dermatologic conditions? Special NACI recommendation re vaccinating young children The Moderna Spikevax (25 µg) COVID-19 vaccine has been recently authorized by Health Canada for primary immunization of children six months to five years of age. As a precaution, the National Advisory Committee for Immunization (NACI) currently suggests that Moderna Spikevax should not routinely be given concurrently (i.e., same day) with other vaccines (live or non-live) in this younger age group. This will allow for monitoring for possible rare or very rare adverse effects following vaccination. NACI currently advises waiting 14 days between vaccine products when administering the Moderna Spikevax COVID-19 vaccine and other vaccines in the six-month to five-year-old age group to prevent erroneous attribution of an adverse effect to one particular vaccine or the other. NACI acknowledges, however, that it may be challenging for healthcare providers and caregivers if multiple healthcare visits are required to administer all recommended immunizations. Therefore, NACI suggests that concurrent administration or a shortened interval between the Moderna Spikevax (25 µg) COVID-19 vaccine and other vaccines may be warranted on an individual basis at the clinical discretion of the healthcare provider.4 References 1. National Advisory Committee on Immunization. Summary of updates in the Canadian Immunization Guide of June 21 2022: Updated guidance on COVID-19 vaccines in Canada. (accessed July 19, 2022). 2. Hause AM, Zhang B, Yue X, et al. Reactogenicity of simultaneous COVID-19 mRNA booster and influenza vaccination in the US. JAMA Network Open 2022;5(7):e2222241. Published online July 15, 2022. (accessed July 19, 2022). 3. Hall KT, Stone VE, Ojikutu B. Reactogenicity and concomitant administration of the COVID-19 booster and influenza vaccine. JAMA Network Open 2022;5(7):e2222246. Published online July 15, 2022. (accessed July 19, 2022). 4. National Advisory Committee on Immunization (NACI). Recommendations on the use of Moderna Spikevax COVID-19 vaccine in children 6 months to 5 years of age. July 14, 2022. (accessed July 19, 2022)

Study examines systemic reaction rates with concurrent COVID-19 and flu vaccines

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