COVID-19, Influenza, and Other Acute Respiratory Viral Infections: Etiology, Immunopathogenesis, Diagnosis, and Treatment. Part 2. Other Acute Respiratory Viral Infections

Durability of Adaptive Immunity in Immunocompetent and Immunocompromised Patients Across Different Respiratory Viruses: RSV, Influenza, and SARS-CoV-2

BACKGROUND/OBJECTIVES

Research on respiratory virus immunity duration post-vaccination reveals variable outcomes. This study performed a literature review to assess the efficacy and longevity of immune protection post-vaccination against SARS-CoV-2, influenza, and respiratory syncytial virus (RSV), with a focus on immunocompromised populations. Specific objectives included examining humoral and cellular immune responses and exploring the impact of booster doses and hybrid immunity on extending protection.

METHODS

A literature review was conducted focusing on studies published from January 2014 to November 2024. The search targeted adaptive immunity post-vaccination, natural immunity, and hybrid immunity for SARS-CoV-2, influenza, and RSV. Selection criteria emphasized human populations, adaptive immunity outcomes, and immunocompromised individuals. The PICO framework guided the analysis, culminating in a detailed review of 30 studies.

RESULTS

SARS-CoV-2 vaccines exhibited robust initial antibody responses, which waned significantly within six months, necessitating frequent boosters. Influenza and RSV vaccines similarly showed declines in immunity, though some influenza vaccines demonstrated moderate durability. Hybrid immunity, arising from combined natural infection and vaccination, provided more resilient and lasting protection than vaccination alone, especially against emerging variants. Immunocompromised individuals consistently exhibited reduced durability in adaptive immune responses across all studied viruses. Challenges include rapid viral mutations, limiting the broad protection of current vaccines.

CONCLUSIONS

Immune durability varies significantly across virus types and patient populations. Frequent boosters and hybrid immunity are critical to optimizing protection, particularly for vulnerable groups. The findings underscore the need for adaptable vaccination strategies and advancements in vaccine design to counter rapidly mutating respiratory pathogens effectively.

Bibliometric Analysis of Human Metapneumovirus Studies

Objective

This study aimed to estimate research productivity and general characteristics of research in different regions of the world in the field of human metapneumovirus (hMPV).

Materials and Methods

We used the Web of Science (WoS) electronic database to retrieve articles on "human metapneumovirus," published up to March 31, 2023. Parameters such as research productivity, the total number of publications, average citation counts of all articles, research productivity by top publishing countries and affiliated organizations, links between countries/organizations, and top keywords were assessed.

Results

We found 826 articles in the WoS database. The first article on hMPV was published in 2002, and 2008 was the year that the most articles on hMPV were published, with 70 articles. The articles were cited 26,797 times (14,498 times without self-citations) and 32.25 times on average per article. Hirsch (H)-index was 80. The year 2008 also had the highest number of citations, with more than 1800. The United States was the most productive country, producing 295 documents (35.714%), one-third of all publications in this field worldwide. Canada (6.5%) and Japan (6.5%) followed the United States regarding total hMPV publications worldwide. The leading funding agencies for hMPV research were from the United States, Europe, China, and Japan.

Conclusion

Our findings imply that developed countries should assist developing countries in enhancing their research infrastructures.