Content provided by CCMS Member: Robert T. Ball. MD MPH FACP 

The 2020-2024 Tridemics of COVID, Influenza, and Respiratory Syncytial Virus (RSV) still require all medical professionals to keep up to date with rapidly expanding legitimate scientific information. Public health/ I.D. experts and official (i.e., CDC websites, not “social media”) can provide accurate information. The collateral epidemic of worsening misinformation (and nefarious dysinformation) is accompanied by an increasing public distrust in medical sciences, public health, and various health care professionals. We must all work hard to remedy these conundra.

COVID

The 2023-2024 global Omicron XBB sub-variants, and the newest US-dominant set of “FLiRT” KP sub-sub-variants, contain even more amino acid mutations and are more likely to escape our immunity (whether from natural infection and/or vaccination). COVID variant tracking data (with a rainbow of colors) are found at https://covid.cdc.gov/covid-data-tracker/#variant-proportions.

These new FLiRT variants are now the most dominant strain in the U.S., now with a summer surge. Other sub-variants will likely continue emerging, as is the pattern with coronaviruses, which seem likely to persist for decades or more to come. The newer variants are a bit more contagious but not quite as virulent than earlier mutants. We pray this pattern persists

The ongoing COVID pandemic is unlike most other well-documented pandemics in that it has persisted for >4 years with innumerable seemingly unrelenting variants (mutations), now an “alphabet soup” to understand. Increasing viral mutations are the virus’ survival adaptation.

COVID virus transmission has not changed much, although public lassitude has. Vaccination rates fell significantly among most groups during the 2020-2022 COVID pandemic (but may be rising). Not unsurprising were the 2023 Omicron variants (and XBB sub-variants), which infected 6x more folks in households and caused increased morbidity and mortality, especially in the unwisely-unvaccinated, very young and old citizens, and those with multiple co-morbidities.

On April 19, 2023 the FDA and CDC approved a bivalent COVID booster to include newer Omicron XBB variants for the fall 2023, but then the US’ FDA and its Vaccine and Related Biological Products Advisory Committee (VRBPAC) voted unanimously to recommend updating the fall 2024 COVID-19 vaccine composition to a monovalent XBB lineage to match these latest Northern hemisphere summer variants.

Wastewater genomic sampling yields reliable and predictable SARS-CoV-2 variants ahead of community clusters or outbreaks. Such testing is now being used for other viral pathogens.

The Centers for Disease Control and Prevention (CDC) tracks the new COVID variants (as data showing its dominance across the United States). CDC predicts that KP.3 is growing and will become the most common SARS-CoV-2 lineage nationally.

Many severe COVID illnesses are now often avoidable due to vaccines and treatments such as nirmatrelvir-ritonavir (Paxlovid), both of which prevent an infection from becoming worse.

Influenza

Influenza “season” persists into spring-summer 2024. 

AMA News 6.13: CBS News (6/12, Tin) reports, “At least two human cases of the new so-called ‘dual mutant’ strains of H1N1 influenza have been detected in U.S. patients, the Centers for Disease Control and Prevention said Wednesday, with genetic changes that could cut the effectiveness of the main flu antiviral that hospitals rely on.” A study investigating “the new H1N1 flu viruses with these two concerning mutations- which scientists call I223V and S247N, describing changes to key surface proteins of the virus.

Influenza hits “seasonally”, although winter 2022-2023 was a bit milder than the prior few years. The CDC states “influenza viruses (including variants) tested to date are susceptible to the neuraminidase inhibitor drugs oseltamivir, peramivir and zanamivir, and the endonuclease inhibitor baloxavir”, which can/ should be used for both treatment and prophylaxis where indicated.

Southern Hemisphere influenza viruses (now their winter) determine the composition of the Northern Hemisphere (NH) vaccines per the World Health Organization (WHO), which recommends that trivalent vaccines for use in the 2023-2024 NH  influenza season contain the following:

Public health experts strongly recommended the latest CDC MMWR monograph “Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices…” available online each mid-August (www.cdc.gov/influenza).

Respiratory Syncytial Virus (RSV), another common “seasonal” pathogen, disproportionally infects younger children and older adults (especially those with chronic medical conditions).  Testing is done via nasal swab real-time reverse transcriptase-polymerase chain reaction (rRT-PCR) and antigen testing, which is highly sensitive.  The FDA on July 17, 2023 approved the single-shot monoclonal antibody (mAb) nirsevimab (brand name Beyfortus) to protect infants and toddlers. Another mAb product is now being reviewed by the ACIP and CDC for prophylaxis approval.- Unfortunately, no RSV-specific treatment is available yet.

Human MetaPneumoVirus (HMPV) is another respiratory virus which has seen a significant increase in incidence in the US in 2022-2023.  Some of the newest respiratory viral PCR panels often include testing for HMPV.  Symptoms are similar to influenza, COVID, and RSV. Morbidity and mortality are similar to those of influenza. Unfortunately current science has neither a vaccine or other prophylaxis,  nor a specific treatment yet.

Whole Genome Sequencing (WGS) or Targeted Genomic Sequencing (TGS) of coronaviruses isolated from bats and intermediate hosts help predict evolution into humans, especially as WGS and TGS are now faster and less expensive.  MUSC and Roper use BioFire for respiratory sample sequencing; the CDC uses a Multiplex system, all of which test selected parts of certain viral genomes.

Some good news includes: 1) COVID boosters will likely be monovalent based on the latest sub-variants; 2) the FDA has now approved two single-dose Respiratory Syncytial Virus (RSV) vaccines for adults > 60yo; 3) influenza vaccines will include more types (and newer strain variants) 4) because of evolving vaccine manufacturing technology, future COVID vaccines will likely be a single-shot per year, then hopefully in a few years in combination with seasonal influenza viruses.

What about other viruses, like “bird flu” ?

To date, the CDC has confirmed 9 human cases of High Pathogenicity Avian Influenza (A-H5N1), all in workers handling infected (sick) cattle or poultry. Person-to-person transmission has not been seen.  Globally, #### cases have been reported to WHO. 

“Since 1997, 912 human cases of High-Path Avian Influenza H5N1 have been confirmed globally, according to the CDC. The large majority of these infections were in people with close contact to infected animals. A small portion of cases are believed to be attributable to human-human transmission, but sustained human-to-human transmission hasn’t been seen.” (June 2024 Popular Science)

Some take-home messages include:

a) keep updating yourself on respiratory pathogens in your community, state, and nation;

b) know that COVID coronaviruses continue to mutate, many morphing into less virulent but still highly transmissible variants (not unlike coronaviruses which comprise about 1/5 of common colds):

c) continue to actively promote folk to keep up to date on all their vaccines (especially COVID boosters);

d) know how to contact local & state experts for information and advice;

e) stress that the COVID pandemic is NOT “over” (although the public is over its major effects [i.e., high mortality] and generally has lost interest, but the virus is NOT done with us).

Robert Ball, MD MPH FACP (843.709.3779)
Assistant Adjunct Professor, Department of Public Health Sciences, MUSC Chair, Chas. Co. Medical Society Public Health Committee
7.2024