Why are COVID-19 rates higher for boosted than vaccinated Californians? – Daily newsletter


Don’t look at California’s COVID-19 cases and hospitalization rates by vaccine status if you’ve had a booster or are considering one: Published numbers suggest you could be just as likely — or more — to get infected if you are boosted than if you only had the initial hits.

Is there a problem with the boosters? Absolutely not, insists one of the state’s top public health officials.

“The key message is that recalls are absolutely extremely important,” said California state epidemiologist Dr. Erica Pan. “Boosters definitely protect you, especially from serious infections and death.”

State health officials and other health analysts attribute the seemingly odd trend to data limitations that don’t distinguish things like how long a person has been on a booster and whether additional injections over time have lost their effectiveness against the latest fast-spreading variants of the virus.

And what is crystal clear is that the latest figures continue to show that people who are not vaccinated at all have higher rates of infection, hospitalization and death than people vaccinated or boosted, state health officials noted.

Data published on California’s online COVID-19 Tracking Dashboard demonstrates the effectiveness of vaccination and boosters in reducing disease risk. In January, at the height of last winter’s spike in cases due to the highly contagious omicron variant, the case rate per 100,000 people was 647.5 for the unvaccinated, 227.4 for the vaccinated and 119.1 for the vaccinated.

At the same time, hospitalization rates per million were 168.5 for the unvaccinated, 34.1 for the vaccinated and 16 for the boosted. Mortality rates per million were 21.7 unvaccinated, 3 vaccinated, and 1.1 vaccinated.

But that started to change in late February, when the number of boosted people began to overtake those who had only received the first hits.

Although rates in all categories have improved since January, the most recent data from May 15 showed a case rate of 105.9 for the unvaccinated, 11.3 for the vaccinated and 22.5 for the vaccinated. . The hospitalization rate was 16 for unvaccinated, 1.5 for vaccinated and 2.2 for boosted. Death rates as of May 8 were 1 for unvaccinated and 0.1 for vaccinated and vaccinated.

Pan said a key limitation in the data is that it doesn’t distinguish when someone got the extra hit. They show up the same in the data, whether it’s September or just last month.

This is a problem because the protection against the virus from previous infection, vaccination or boosters decreases over time as anti-virus antibodies in the body wane and the virus mutates to evade immunity.

Another limitation, Pan said, is that most people who received boosters tend to be at higher risk initially, older and in poorer health. This is why they were prioritized for boosters initially. But it also means they are more susceptible to infection, serious illness and death.

Additionally, hospitalization data does not distinguish between those admitted with severe symptoms of COVID-19 and those who came with something else and were also found to have COVID-19 by screening tests. routine upon admission.

So a boosted patient with a mild breakthrough infection who went to the hospital for a broken ankle appears in the data the same as a boosted person who was intubated with oxygen for COVID. -19 severe.

A Rockefeller Foundation blog post in April highlighted numerous data issues that can produce misleading images of breakthrough infections. Among other challenges, he noted that obtaining accurate information on the ever-changing size of vaccinated and boosted populations is critical to providing meaningful rates.

The authors – data scientists Kara Schechtman, Dr Dave Luo, Jonathan Gilmour and Kaitlyn Johnson, public health adviser Dr Lindsey Shultz, public health researcher Rebecca Glassman, Dr Jacqueline Houtman and Jessica Malaty Rivera of the Pandemic Tracking Collective and Pandemic Prevention Institute director Leo Wolansky said existing data makes it increasingly difficult to assess the risks of a breakthrough.

“As new variants emerge in a population with an increasingly complex vaccination landscape, we hope that states and jurisdictions will become more transparent about their methodologies and limitations,” the post reads. “The lack of consistency in state reporting is one of the reasons our team decided to stop collecting groundbreaking data.”

California health officials said recent studies from the Centers for Disease Control and Prevention on the actual effectiveness of vaccines and boosters continue to demonstrate their value. Among them was a study on the effectiveness of vaccines against hospitalization due to the virus and another on their protection against serious illnesses requiring ventilation.

“The really important message,” Pan said, “is that when you look at the unvaccinated versus those who got two doses or boosters, there’s still this big difference, that vaccination protects you overall.”


Comments are closed.