So-called “hybrid immunity”—from vaccination and infection—offers better protection against severe illness and hospitalization from COVID than immunity from infection alone, according to the a new study published in The Lancet.
The study provides public health officials and policy makers with recommendations on priorities when running vaccination campaigns, and on the potential frequency of booster shots going forward.
The World Health Organization, which collaborated on the study, touted it Wednesday for “demonstrating the benefits of vaccination even when people have COVID-19.”
Those who developed hybrid immunity had a 95% lower chance of becoming seriously ill with COVID or requiring hospitalization a year later, according to the study, which analyzed data from 26 other studies. Those who were previously infected but not vaccinated experienced reduced protection against the same. Their risk was only 75% lower, the researchers found.
Those with hybrid immunity after their first two COVID shots were nearly 42% less likely to be reinfected with COVID at one year, and nearly 47% less likely six months later. their first booster vaccination. For those infected but not vaccinated, protection is only 25% at 12 months.
Because those with hybrid immunity have the highest level of protection against COVID, in addition to the longest duration, they can wait six months after infection or vaccination to receive a booster dose, the authors said.
Decision makers could use the study’s findings to tailor vaccine recommendations in a region, the study suggests. When resources are scarce in a region where most are infected with COVID and there are competing health priorities, authorities may choose to focus on vaccinating high-risk populations with a two-shot primary series of vaccines only.
Given that immunity against severe disease and illness is still strong for a year, mass vaccination campaigns can be implemented before an unexpected annual outbreak, such as in winter, the authors added.
They warn, however, against creating a nuanced vaccine guide that is complex to understand and can, thus, reduce consumption.
Because Omicron is easily transmissible compared to previous variants of COVID, it significantly increases the rate of infection and, thus, a measure of resistance, although declining, worldwide, the WHO said in a June statement. In February 2021, shortly after the rise of Omicron, the global public health organization estimated that 16% of the world’s population was infected. In October of the same year, that estimate increased to 67%.
Learn how to navigate and build trust in your business with The Trust Factor, a weekly newsletter that explores what leaders need to succeed. Sign up here.