COVID-19 Roundup: Janssen Vaccine Use, Seroprevalence of Infection, Neurologic Symptoms, Adverse Outcomes In Unvaccinated Individuals

FDA Limits Use of COVID-19 Vaccine1

The US Food and Drug Administration (FDA) has restricted the use of the Janssen COVID-19 vaccine in most patient populations.

The Jansen vaccine is now authorized for use only in individuals aged 18 years or older who are unable to receive other authorized or approved COVID-19 vaccines due to access or clinical appropriateness, and individuals aged 18 years or older who want the Jansen vaccine and would otherwise not receive a COVID-19 vaccine.

This decision comes as a result of an analysis on the risk of thrombosis with thrombocytopenia syndrome (TTS), a rare but potentially fatal syndrome that results in blood clots and low levels of blood platelets. A total of 60 cases of TTS have been reported to the Vaccine Adverse Event Reporting System.

Seroprevalence of COVID-19 Infections2

More than half of the American public has been infected with COVID-19, according to the results of a recent national survey from the Centers for Disease Control and Prevention (CDC).

Researchers examined the seroprevalence of antibodies produced only during a COVID-19 infection to better understand the amount of asymptomatic, undiagnosed, or unreported COVID-19 infections within the United States from September 2021 to February 2022.

The results indicated the overall seroprevalence increased from 33.5% in December 2021 to 57.7% in February 2022. Additionally, approximately 75% of children and adolescents had evidence of previous COVID-19 infection as of February 2022, of which a third were newly infected from December 2021. Age groups with the lowest vaccination coverage had the highest increase of seroprevalence from September 2021 to February 2022.

Neurologic Symptoms Following COVID-193

Serious neurologic manifestations, such as stroke and seizure, occurred in 12.9% of individuals hospitalized with COVID-19.

Included in this prospective observational study were 16,225 individuals from 179 hospitals within 24 countries.

Of the total individuals included, 10.2% (n = 1656) had encephalopathy at admission. At admission or during the course of hospitalization, 2.0% (n = 331) developed stroke, 1.5% (n = 243) with seizure, and 0.5% with meningitis/encephalitis. These serious neurologic symptoms were associated with more severe disease, a higher likelihood of being admitted to the intensive care unit and to require critical care interventions.

Serious Complications in Unvaccinated Individuals4

Individuals with heart problems who are not vaccinated against COVID-19 are 9 times more likely to suffer adverse outcomes and events following COVID-19 infection.

Researchers examined the relationship between hypertension (HTN), diabetes mellitus (DM), ischemic heart disease (IHD), and myocardial injury on the risk of death, acute respiratory distress syndrome, invasive mechanical ventilation, admission to the intensive care unit, acute kidney injury, and severe disease. They conducted a meta-analysis of 110 studies, consisting of 48,809 individuals with COVID-19 between December 2019 and July 2020.

“COVID-19 patients with myocardial injury are at substantially greater risk of death, severe disease and other adverse outcomes,” researchers concluded. “Weaker, yet significant associations are present in patients with HTN, DM, and IHD. Quantifying these associations is important for risk stratification, resource allocation and urgency in vaccinating these populations.”


—Leigh Precopio



  1. Coronavirus (COVID-19) update: FDA limits use of Janssen COVID-19 vaccine to certain individuals. News release. US Food and Drug Administration; May 5, 2022. Accessed May 9, 2022.
  2. Clarke KEN, Jones JM, Deng Y, et al. Seroprevalence of infection-induced SARS-CoV-2 Antibodies – United States, September 2021 – February 2022. MMWR mob Moral Wkly Rep. 2022;71(17):606-608. doi:10.15585/mmwr.mm7117e3
  3. Cervantes-Arslanian AM, Venkata C, Anand P, et al. Neurologic manifestations of severe acute respiratory syndrome coronavirus 2 infection in hospitalized patients during the first year of the COVID-19 pandemic. Crit Care Explor. 2022;4(4):p e0686. doi:10.1097/CCE.0000000000000686
  4. Ng SM, Pan J, Mouyis K, et al. Quantifying the excess risk of adverse COVID-19 outcomes in unvaccinated individuals with diabetes mellitus hypertension, ischemic heart disease, or myocardial injury: a meta-analysis. Front Cardiovasc Med. Published online April 26, 2022.