When it Comes to the Monovalent COVID-19 Shot, the CDC and WHO Have a Disagreement

In September, the Centers for Disease Control and Prevention (CDC) recommended that all Americans over the age of 6 months receive the new monovalent COVID-19 vaccine based on high circulation of the XBB.1.5 SARS-CoV-2 variant. The World Health Organization (WHO) has recommended a more nuanced approach with patients being placed into one of 3 groups: high, medium, and low priority.

Per the WHO, only the high-risk group (ie, (eg, elderly, immune suppressed, pregnant, obese, and those with preexisting heart and lung disease) needs routine vaccination with the new COVID vaccine.

Paul Offit, MD, a leader of the fight against the antivaccine movements, describes the US as an “outlier” with its universal recommendation while the WHO and many West European countries (UK, Sweden, Germany, Finland, Norway) support limiting use of the new vaccine to high-risk groups. It is not unusual for different expert agencies to offer different recommendations. The FDA and CDC, for example, disagree in many areas on small matters, one example being on the interchangeability of vaccines from different manufacturers against the same diseases.

Why the difference of opinion between the CDC and WHO on this flashpoint topic?

One could argue that countries with government paid health care are more concerned with cost effectiveness. Those same countries might counter with an argument that a lower benefit/risk ratio suggests that only high-risk persons be vaccinated. At the meeting of the CDC’s Advisory Committee on Immunization Practices in September, at which the universal approach was recommended, data were presented showing that deaths and hospitalizations from COVID continue in all age groups and even in persons without any risk factors. When the Omicron variant emerged in November 2021 many previously vaccinated persons developed mild disease with some increase in hospitalizations and deaths. The CDC in 2022 produced studies showing that booster shots did help reduce infections from the new variant with the high-risk populations deriving the most benefit by far.

Let's look at some data.

Last year the CDC recommended universal (ie, everyone over the age of 6 months) vaccination with the bivalent vaccine (original plus an Omicron variant). A matched prospective cohort study done in the Kaiser Permanente Southern California patient population looked at bivalent vaccine effectiveness in preventing hospitalization as compared to vaccination with at least 2 doses of any monovalent mRNA vaccine.

Question 1. What was the overall vaccine effectiveness in persons over the age of 17 years in preventing hospitalization in the 3 months following bivalent vaccine receipt?

As of May 10, 2023, the CDC reported that 92.3% of the American population older than age 18 years had received at least 1 dose of any COVID vaccine.

Question 2. What proportion of the same age group received the bivalent vaccine?