Reporting on the Moderna mRNA vaccine showed anaphylaxis rates of about 2.5 per 1 million doses, with 50% of the recipients who experienced true anaphylaxis having a history of anaphylaxis. Most of those who experienced anaphylaxis (90% in the Moderna group and 86% in the Pfizer group) exhibited symptoms of anaphylaxis within 30 minutes of receiving the vaccine. The take-home point, and the current CDC recommendation, is that many individuals, even those with a history of anaphylaxis, can still receive COVID-19 vaccines. The rates of observed anaphylaxis after COVID vaccination are far below population rates of a history of allergy or severe allergic reactions. When coupled with an estimated mortality rate of 0.5%-1% for SARS-CoV-2 disease, that CDC recommends that we encourage people, even those with severe allergies, to get vaccinated.
One clear caveat is that individuals with a history of severe anaphylaxis, and even those concerned about allergies, should be observed for a longer period after vaccination (at least 30 minutes) than the 15 minutes recommended for the general population. In addition, individuals with a specific anaphylactic reaction or severe allergic reaction to any injectable vaccine should confer with an immunologist before considering vaccination.
Another useful resource is a column published by the American Medical Association that walks through some talking points for providers when discussing whether a patient should receive COVID-19 vaccination. Advice is offered on answering patient questions about which preparation to get, what side effects to watch for, and how to report an adverse reaction. Providers are reminded to urge patients to complete whichever series they begin (get that second dose!), and that they currently should not have to pay for a vaccine. FAQ resource pages are available for patients and health care providers.
More vaccine news: HPV and influenza
Meanwhile, published vaccine reports provide evidence from the field to demonstrate the benefits of vaccination. A study published in the New England Journal of Medicine reported on the effectiveness of human papillomavirus (HPV) vaccine in a Swedish cohort. The report evaluated females aged between 10 and 30 years beginning in 2006 and followed them through 2017, comparing rates of invasive cervical cancer among the group who received one or more HPV vaccine doses with the group who receive none. Even without adjustment, the raw rate of invasive cervical cancer in the vaccinated group was half of that in the unvaccinated group. After full adjustment, some populations experienced incident rate ratios that were greater than 80% reduced. The largest reduction, and therefore the biggest benefit, was among those who received the HPV vaccine before age 17.
A report from the United States looking at the 2018-2019 influenza season demonstrated a vaccine effectiveness rate against hospitalization of 41% and 51% against any ED visit related to influenza. The authors note that there was considerable drift in the influenza A type that appeared late in the influenza season, reducing the overall effectiveness, but that the vaccine was still largely effective.
William T. Basco Jr, MD, MS, is a professor of pediatrics at the Medical University of South Carolina, Charleston, and director of the division of general pediatrics. He is an active health services researcher and has published more than 60 manuscripts in the peer-reviewed literature.
A version of this article first appeared on Medscape.com.