Respiratory Roundup

On April 18, the World Health Organization (WHO) published a global technical consultation report announcing updated terminology for pathogens that transmit through the air. The pathogens covered include those that cause respiratory infections, e.g. COVID-19, influenza, measles, Middle East respiratory syndrome (MERS), severe acute respiratory syndrome (SARS), and tuberculosis, among others.

A press release on the announcement says that “The publication, entitled ‘Global technical consultation report on proposed terminology for pathogens that transmit through the air,’ is the result of an extensive, multi-year, collaborative effort and reflects shared agreement on terminology between WHO, experts and four major public health agencies: Africa Centres for Disease Control and Prevention; Chinese Center for Disease Control and Prevention; European Centre for Disease Prevention and Control; and United States Centers for Disease Control and Prevention. This agreement underlines the collective commitment of public health agencies to move forward together on this matter.”

Further, “The wide-ranging consultation was conducted in multiple steps in 2021-2023 and addressed a lack of common terminology to describe the transmission of pathogens through the air across scientific disciplines. The challenge became particularly evident during the COVID-19 pandemic as experts from various sectors were required to provide scientific and policy guidance. Varying terminologies highlighted gaps in common understanding and contributed to challenges in public communication and efforts to curb the transmission of the pathogen.”

The following common descriptions are now being used to characterize the transmission of pathogens through the air, under typical circumstances:

• Individuals infected with a respiratory pathogen can generate and expel infectious particles containing the pathogen, through their mouth or nose by breathing, talking, singing, spitting, coughing, or sneezing—these particles should be described with the term “infectious respiratory particles” (IRPs)
• IRPs exist on a continuous spectrum of sizes, and no single cutoff points should be applied to distinguish smaller from larger particles—this facilitates moving away from the dichotomy of previously used terms: ‘aerosols’ (generally smaller particles) and ‘droplets’ (generally larger particles)

Under the umbrella of ‘through the air transmission’, two descriptors can be used:

• Airborne transmission or inhalation
• Direct deposition

On June 26, the CDC updated its recommendation for the use of Respiratory Syncytial Virus (RSV) vaccines in people ages 60 and older. For this upcoming respiratory virus season, CDC recommends:

• Everyone ages 75 and older receive the RSV vaccine.
• People ages 60–74 who are at increased risk of severe RSV, meaning they have certain chronic medical conditions, such as lung or heart disease, or they live in nursing homes, receive the RSV vaccine.

This recommendation is for adults who did not get an RSV vaccine last year. The RSV vaccine is not currently an annual vaccine, meaning people do not need to get a dose every RSV season. Eligible adults can get an RSV vaccine at any time, but the best time to get vaccinated is in late summer and early fall before RSV usually starts to spread in communities.

The updated recommendation for people 60 and older replaces the recommendation made last year to simplify RSV vaccine decision-making for clinicians and the public.

Immunizations were available last year for the first time to protect people at increased risk for severe RSV, including infants and young children, and people ages 60 and older. The updated recommendation is based on analyses of RSV disease burden among people 60 and older, as well as RSV vaccine effectiveness and cost-effectiveness studies. Those studies included the first real-world data since RSV vaccines were recommended for people 60 and older.

Healthcare providers should recommend RSV vaccines to their eligible patients, as well as discuss what other vaccines they will need this fall to help prevent respiratory infections.

In August, HHS launched a new national campaign, called Risk Less. Do More., which aimed to “increase awareness of vaccines that reduce serious illness from influenza (flu), COVID-19, and respiratory syncytial virus (RSV) in high-risk populations and to limit the spread of these viruses among all Americans.”

HHS is hoping to get ahead of a potential uptick in cases over the coming fall and winter. Last fall and winter, “these infections caused 800,000 hospitalizations. Without immunization, the risk of serious illness remains highest in certain populations, including adults ages 65 and older, residents of long-term care facilities, pregnant people, and those living in rural areas. Some racial and ethnic groups, including Black and Hispanic populations in the United States, are also at higher risk.”

Risk Less. Do More. will “deliver research-based messages through paid advertising and media coverage on TV, radio, print, social, digital, and out-of-home platforms. The campaign will reach all audiences, with a particular focus on those at highest risk, including older Americans and people who may have less access to healthcare information and support, with facts about life-saving vaccines that can help them avoid severe illness.”

In October, CDC confirmed two human cases of H5 bird flu in California. Both of the cases occurred in people with “occupational exposure to infected dairy cows.”

This identification in people exposed to infected animals is “not unexpected and does not change CDC's risk assessment for the general public, which continues to be low. At this time, there is no known link or contact between the first and second confirmed cases in California, suggesting these are separate instances of animal-to-human spread of the virus.”

These cases are the first among humans in California, “where H5N1 outbreaks among dairy herds were first reported in August 2024. H5N1 bird flu was detected for the first time in cows this year in the United States.” Including this most recent case, “16 human cases of H5 have been reported in the United States during 2024, bringing the total to 17 cases since 2022. Cases during 2024 have been reported in Texas (1), Michigan (2), Colorado (10), Missouri (1) and California (2). Six of the 16 reported human cases have been linked to exposure to sick or infected dairy cows. Nine cases had exposure to infected poultry. The source of infection for the one case in Missouri has not been determined.”

HPN has reported on these H5N1 outbreaks over the past year.