Hybrid immunity which combines vaccination and infection provides the most robust protection against severe disease, hospitalization, and death, cautions the peer-reviewed journal in its latest article

As the US continues to emerge from the pandemic it is essential that clinicians and patients keep SARS-CoV-2 on the list of viral pathogens that cause major respiratory illness, says JAMA, a peer-reviewed medical journal published by the American Medical Association.

In its latest article “COVID-19 in the Fall of 2023—Forgotten but Not Gone” authors Carlos del Rio, Preeti N. Malani, say protecting the most vulnerable populations should be a priority with making vaccinations, high-quality masks, testing, and antivirals easily available.

“Finally, perhaps the most important way to limit transmission is self-isolation of those who are infected. Regardless of test results, any person with symptoms of a respiratory infection should remain home and avoid going to school or work,” the authors say.

They continue: “While COVID-19 is no longer a public health threat, waves of infection will occur for the foreseeable future. How disruptive these are will depend on the behavior of the virus but also, more importantly, on the behavior of humans.”

With the end of the Public Health Emergency, COVID-19 surveillance in the US is no longer performed using case counts. Instead, wastewater surveillance and tracking of hospitalizations and deaths are the major indicators being used to understand trends. Since late June 2023, there has been a steady increase in the detection of SARS-CoV-2 in wastewater, a change that correlates with a bump in reported hospitalizations and deaths, the article reveals.

However, these increases are small compared with those seen early in the pandemic when most of the population lacked any protective immunity to the virus and infection not uncommonly led to severe illness and even death for a substantial proportion of those infected.

As a result of vaccination and infection, population immunity has increased. By the end of 2022, an estimated 97% of people aged 16 years or older had infection or vaccination-induced antibodies, and the estimated age-adjusted COVID-19–associated death rate decreased 47%, from 115.6 per 100 000 persons in 2021 to 61.3 per 100 000 persons in 2022.

Hybrid immunity (vaccination plus infection) provides the most robust protection against severe disease, hospitalization, and death. However, the prevalence of hybrid immunity appears to be lowest among those aged 65 years and older, and immunity from vaccines wanes over time and that decrease is faster among older adults.

This is why the US Centers for Disease Control and Prevention (CDC) has recommended that those 65 years and older receive an additional booster.

Since the initial emergence of the Omicron variant in November 2021, the virus has continued to rapidly evolve, acquiring mutations that provide it with increasing immune escape.

COVID-19 vaccination is recommended for everyone 6 months and older in the US. Vaccination is safe and effective and protects against the most serious effects of SARS-CoV-2 infection, specifically hospitalization and death. However, protection against symptomatic infection is limited, and waning of immunity is a reality with the currently available vaccines.

Among adults who are otherwise healthy, recent estimates of vaccine effectiveness of a bivalent vaccine against hospitalization for COVID-19 were 62% compared with no vaccination in the two months after the bivalent dose but decreasing to 24%, four to six months after the bivalent dose.

The CDC considers an individual who has completed a primary series and received a single booster as “up to date” in their COVID-19 vaccination. If they have completed a primary series and are not yet eligible for a booster, they are also up to date.

However, an individual who has completed a primary series and is eligible for a booster but has not received a booster is not up to date. For people aged 65 years and older, there is the option to receive one additional bivalent mRNA vaccine dose if it has been at least 4 months since their first bivalent vaccine dose.

Also Read : Doctors should use #MedEd to reach millions, debunk misinformation: JAMA