In a new study from the Providence Research Network, researchers confirmed the overall effectiveness of vaccines in preventing severe infection resulting in hospitalization from COVID-19, but also shows a substantial decline in protection after six months.
They examined data from nearly 50,000 hospital admissions between April and November of 2021.
They found that vaccines were 94% effective at preventing hospitalization 50-100 days after receiving the shot but fell to 80.4% 200-250 days later, with even more rapid declines after 250 days.
The study was also able to identify factors associated with reduced vaccine effectiveness.
Key risk factors for a severe “breakthrough” infection included advanced age (80+), comorbidities such as cancer, transplants, chronic kidney disease, hypertension, or heart failure, the amount of time that had elapsed since being vaccinated, and the type of vaccine one received.
For the latter factor, the study found that the Moderna vaccine offered the best overall protection over time, while the Pfizer-BioNTech vaccine offered initial protection equivalent to Moderna’s but declined more rapidly over time.
Persons receiving the Janssen vaccine also had higher odds of experiencing a severe breakthrough infection compared to Moderna.
This study helps understand differences in waning protection by vaccine type and identify the key risk factors for severe breakthrough infections to help inform the targeting of potential vaccine booster programs.
Overall, the data support the importance of vaccinations for protection against hospitalization, and also clearly evidences the need to boost that protection after 200 days, particularly for patients age 80 and up or with specific medical conditions that increase their risk of severe infection.
If you care about Covid, please read studies about the key to curing COVID-19, and familiar drug that may help treat COVID-19.
For more information about Covid, please see recent studies about two paths toward ‘super immunity’ to COVID-19, and results showing that CBD from cannabis may inhibit COVID-19 infection.
The study is published in The Lancet Respiratory Medicine.
Copyright © 2022 Knowridge Science Report. All rights reserved.
