Can Vaccines Promote Herd Immunity

Adult Influenza Vaccine

Introduction

Influenza is a contagious respiratory illness caused by influenza viruses that affects millions of people globally every year and can cause morbidity and mortality among older adults and those with underlying health conditions (Javanian et al., 2021). Vaccination is considered by many in the medical community to be the best preventive measure against influenza. This discussion will focus on the influenza vaccine and look at its safety concerns and clinical effectiveness in promoting health across the lifespan, especially in adults and the older populations.

Clinical Effectiveness of the Influenza Vaccine

The clinical effectiveness of the influenza vaccine varies with age and health status (Lee et al., 2021). In healthy adults, the vaccine\\\\\\\'s efficacy can range from 40% to 60%, depending on the match between the vaccine strains and the circulating strains of the virus. For older adults, the efficacy tends to be lower due to immunosenescence, which is a decline in immune function with age (Lee et al., 2021). However, the vaccine can still be viewed by medical providers as beneficial for the elderly because of the claims that it significantly reduces the severity of illness, the need for hospitalization, and the risk of complications such as pneumonia and any worsening of already existing chronic conditions (Tenforde et al., 2021).

The widespread use of the influenza vaccine is also believed to be a contributor to herd immunity, which is said to reduce the overall circulation of the virus in the community (Marlowe et al., 2022). This effect protects vulnerable populations, including infants who are too young to be vaccinated and people with compromised immune systems. Annual vaccination is recommended by most medical providers as being a good protector against the predominant strains of influenza virus, which are believed to change each year, and which is why updated vaccines to provide protection are recommended (Marlowe et al., 2022).

Influenza vaccination is also said to reduce the incidence of flu-related medical visits, hospitalizations, and deaths. Researchers have argued that vaccination can prevent millions of flu cases and thousands of hospitalizations and deaths each year. This reduction in disease burden translates to decreased healthcare costs and less strain on healthcare resources, particularly during peak flu seasons (Lee et al., 2021).

Safety Concerns of the Influenza Vaccine

The influenza vaccine has what is considered to be well-established safety profile (Tenforde et al., 2021). Most side effects are believed to be mild and transient, such as soreness at the injection site, fever, and muscle aches; and these side effects typically resolve within a few days and do not pose serious health risks. However, serious adverse events following influenza vaccination can and do occur. One such event is Guillain-Barré Syndrome (GBS), a condition where the immune system attacks the nerves, causing muscle weakness and paralysis (Koike & Katsuno, 2021). The risk of GBS after vaccination is estimated at approximately one to two cases per million vaccinations, and the risk of developing GBS after natural influenza infection is thought to be higher than after vaccination.

Most influenza vaccines are produced using egg-based manufacturing processes, which has raised concerns for people with egg allergies. However, studies have shown that the risk of an allergic reaction to the vaccine is very low, even in those with severe egg allergies (Lee et al., 2021). For those concerned about this allergy, egg-free vaccine options are available and are recommended by medical providers.

Vaccine safety can be continuously monitored through systems like the Vaccine Adverse Event Reporting System (VAERS) and the Vaccine Safety Datalink (VSD), which are systems that collect data on adverse events following vaccination and are helpful for identifying potential safety concerns. This system of surveillance helps so that any safety signals can be quickly addressed.

Promoting Health Across the Lifespan

Given the reduced immune response in older adults, high-dose influenza vaccines or adjuvanted vaccines have been developed, and these formulations have been designed to elicit a stronger immune response and thereby give better protection for the elderly (Lee et al., 2021). The evidence suggests shown that high-dose vaccines are more effective in preventing flu in older adults compared to standard-dose vaccines (Lee et al., 2021).