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mRNA Vaccines Are Protective Against Worst COVID-19 Outcomes

Healthy Americans who are up-to-date on their mRNA vaccinations have an almost negligible risk of having to go on invasive mechanical ventilation or dying in the hospital from COVID-19. Even taking into account older, sicker and immunocompromised patients, the shots still are 90% protective against those outcomes, according to the CDC. Here are more details.

ATLANTA – The COVID-19 mRNA vaccines are highly protective against the worst outcomes of infection with SARS-C0V-2 infection, including death.

A new article in the Morbidity & Mortality Weekly Report advises that having 2 or 3 doses of the Moderna or Pfizer-BioNTech mRNA vaccines was associated with a 90% reduction in risk for COVID-19–associated invasive mechanical ventilation (IMV) or death.

Protection of 3 mRNA doses was even greater, 94%, during the period of Omicron predominance, the national Centers for Disease Control and Prevention authors add.

Past research has shown how effective the two COVID-19 mRNA vaccines (BNT162b2 [Pfizer-BioNTech] and mRNA-1273 [Moderna]) are at preventing COVID-19–associated hospitalization. This study took that a step further, however, and examined how well mRNA vaccines protect against the most severe outcomes of those hospitalizations.

Researchers used a case-control design to evaluate adults hospitalized at 21 U.S. medical centers from March 11, 2021–January 24, 2022. During that period, the most commonly circulating variants of SARS-CoV-2were B.1.1.7 (Alpha), B.1.617.2 (Delta), and B.1.1.529 (Omicron).

Results indicate that among 1,440 COVID-19 case-patients who received IMV or died, 307 (21%) had received 2 or 3 vaccine doses before illness onset. Among 6,104 control-patients, 4,020 (66%) had received 2 or 3 vaccine doses.

The 1,440 case-patients with unfavorable outcomes – either receiving IMV or dying—despite vaccination tended to:

• Be older (median age = 69 years),
• Be more likely to be immunocompromised (40%), and
• Had more chronic medical conditions compared with unvaccinated case-patients.

“COVID-19 mRNA vaccines are highly effective in preventing COVID-19–associated death and respiratory failure treated with IMV,” the authors write, adding, “CDC recommends that all persons eligible for vaccination get vaccinated and stay up to date with COVID-19 vaccination.”

 Researchers point out that protection “against asymptomatic or milder infection might be reduced by waning of neutralizing antibody levels after vaccination or by immune evasion by emerging variants. However, vaccination stimulates long-lasting memory B and T-cell responses that might limit severity of illness in infected adults. Some studies have found that COVID-19 vaccines provided reduced protection against milder infection. The findings of this study indicate that COVID-19 vaccines provide strong protection against severe COVID-19 resulting in respiratory failure or in-hospital death.”

The report notes that most hospitalized patients had multiple chronic medical conditions, and the overall VE observed in the analysis might actualy underestimate protection in healthier populations. “VE against COVID-19–associated IMV or in-hospital death in adults without chronic medical conditions was highest at 98%,” the authors advise.

They add that “although VE was lower for adults with immunocompromising conditions, most of these persons had not received the third mRNA vaccine dose recommended as part of a primary vaccine series for immunocompromised persons,” so they would expect the protection to increase with that.

The CDC explains that immunocompromising conditions included having one or more of the following conditions: active solid organ cancer (active cancer defined as treatment for cancer or newly diagnosed cancer in the past 6 months); active hematologic cancer (e.g., leukemia, lymphoma, or myeloma); HIV infection without AIDS; AIDS; congenital immunodeficiency syndrome; previous splenectomy; previous solid organ, stem cell, or bone marrow transplant; immunosuppressive medication; systemic lupus erythematosus; rheumatoid arthritis; psoriasis; scleroderma; or inflammatory bowel disease, including Crohn’s disease or ulcerative colitis.