Estimated Number of Adults With Long COVID, WHO Updates Terminology For Air Pathogens, Vaccination Reduces Risk of Cardiac Events, and More

Anthony Calabro, MA

Survey: Approximately 17 Million Adults Have Long COVID1

As of March 2024, 7% of all adults, which equates to roughly 17 million people, reported that they have long COVID, according to the latest self-reported data from the Household Pulse Survey conducted by the Census Bureau and National Center for Health Statistics. Additionally, according to a recent analysis of the survey,60% of adults reported having COVID at some point, and of those 60%, approximately three in 10 reported having long COVID at some point. Further, one in 10 said they currently have long COVID.

The CDC broadly defines long COVID as “signs, symptoms, and conditions that continue or develop after acute COVID-19 infection.” The length of time these symptoms persist varies, ranging from days, weeks, months, or longer, according to the CDC.

The survey also found that most individuals with long COVID have had their activities limited in some capacity. The survey asked those with long COVID whether their activities have been limited “a lot”, “a little”, or “not at all”, with the “a lot” responses being characterized as “significant.” Only 21% of respondents said their activities were not limited, while 25% reported that long COVID limits their activities “a lot.”

Most people report activity limitations, but only one in four reported long COVID limits their activities a lot. These numbers have changed little since the Pulse survey first started asking about activity limitations in September 2022,” the analysis noted.

WHO Updates Terminology for Pathogens That Transmit Through the Air2

The WHO recently published a report updating the terminology for pathogens that transmit through the air. The update covers pathogens that cause respiratory infections, including COVID-19.

The objective of the report was to address a lack of common terminology across scientific disciplines describing the transmission of pathogens through the air—an issue that was highlighted during the pandemic. Experts from various scientific areas provided scientific and policy guidance throughout the pandemic. But when doing so, they often used differing descriptors in their guidelines, which “contributed to challenges in public communication and efforts to curb the transmission of the pathogen,” the WHO summary report acknowledged.

The report includes updated descriptors for the transmission of pathogens through the air. For example, infectious particles containing respiratory pathogen that are transmitted through one’s mouth or nose, or by breathing, talking, spitting, coughing, or sneezing should be termed “infectious respiratory particles” or IRPs for short. Importantly, IRPs will not be distinguished by size, which is a departure from previously used terms like “aerosols” or “droplets” that included associated size components.

Additionally, “through the air” can be used as an umbrella term for an infectious disease where the main mode of transmission involves the pathogen moving through the air. Under that umbrella term, two descriptors are recommended:

  • Airborne transmission or inhalation: used when IRPs are expelled into the air and inhaled by another person.
  • Direct deposition: used when an infectious person puts IRPs into the air and are directly deposited on the exposed mouth, nose, or eyes of another person, ultimately causing infection.

“The agreed terminology for pathogens that transmit through the air will help set a new path for research agendas and implementation of public health interventions to identify, communicate and respond to existing and new pathogens,” said Sir Jeremy James Farrar OBE, FRCP, FRS, FMedSci, WHO chief scientist.

COVID-19 Vaccination Reduces Risk of Cardiac Events After Infection3

A recent study found that COVID-19 vaccines reduced the risk of heart failure and blood clots following COVID-19 infection.

The study, which included more than 20 million people, used electronic health records from the United Kingdom, Spain, and Estonia to determine how COVID-19 vaccines impact post-infection cardiovascular complications, including venous thromboembolism (VTE), arterial thrombosis/thromboembolism (ATE), and heart failure (HF).

Of the more than 20 million people included in the study, approximately half were vaccinated (n = 10.2 million) and half were not (n = 10.4 million). Researchers recorded the cardiovascular complications in four windows after COVID-19 infection: 0-30 days, 31-90 days, 910-180 days, and 181-365days.

The study showed that COVID-19 vaccines reduced post-infection risks of VTE, ATE, and HF in the acute (0-30 days) and post-acute phases of infection (31-365 days).

“COVID-19 vaccination reduced the risk of post-COVID-19 cardiac and thromboembolic outcomes,” the authors concluded. “These effects were more pronounced for acute COVID-19 outcomes, consistent with known reductions in disease severity following breakthrough versus unvaccinated SARS-CoV-2 infection.”

“Persistent Impairments” At 1 Year Among Those With Prolonged Severe COVID-194

In a national, multicenter, prospective longitudinal cohort study, researchers investigated the persistent health problems among hospitalized adults discharged to long-term acute care hospitals (LTACHs) for prolonged severe COVID-19 illness who survived 1 year.

For their study, researchers included hospitalized adults who were transferred to one of nine LTACHs in the United States between March 2020 and February 2021 and completed a survey. Of the 282 eligible participants who provided permission to be contacted, 156 (55.3%) participated in the survey.

The survey results indicated that the median age of the participants was 65 years, the majority of which were men (61.5%). The median length of stay at the LTACH was 57 days, 77% were mechanically ventilated for a median of 26 days, and 42% had a tracheostomy.

Further, approximately 64% had a persistent impairment: 57% had a physical impairment, 49% had a respiratory impairment (19% of which were on supplemental oxygen), 24% indicated a psychiatric impairment, and 15% noted a cognitive impairment. Almost half of those who participated in the survey (47%) had two or more impairment types.

“Participants also experienced persistent debility from hospital-acquired complications, including mononeuropathies and pressure ulcers,” the authors noted. “Participants described protracted recovery, attributing improvements to exercise/rehabilitation, support, and time.”

Although most respondents (78.7%) noted that they were not returning to their usual health, 99% returned home, and 60% of those who previously had a job returned to work.

Nearly two-thirds of survivors of among the most prolonged severe COVID-19 illness had persistent impairments at 1 year that resembled post-intensive care syndrome after critical illness plus debility from hospital-acquired complications,” the researchers concluded.


  1. Burns A. As recommendations for isolation end, how common is long covid? KFF; April 9, 2024. Accessed May 1, 2024.
  2. Leading health agencies outline updated terminology for pathogens that transmit through the air. News release. World Health Organization; April 18, 2024. Accessed May 1, 2024.
  3. Mercadé-Besora N, Li X, Kolde R, et al. The role of COVID-19 vaccines in preventing post-COVID-19 thromboembolic and cardiovascular complications. Heart. 2024;110(9):635-643. doi:10.1136/heartjnl-2023-323483
  4. Makam AN, Burnfield J, Prettyman E, et al. One-year recovery among survivors of prolonged severe COVID-19: a national multicenter cohort. Crit Care Med. Published online April 10, 2024. doi:10.1097/CCM.0000000000006258