Question

The flu has been around since 1918. Why are the vaccines against Covid, which is much newer and more harmful, so much more effective than the flu vaccines? Is there any hope for a 'universal flu vaccine' (as there is for a 'universal Covid vaccine')?

Answer 1

It is important to clarify a few points regarding the flu and COVID-19 vaccines:

1. COVID-19 is caused by the SARS-CoV-2 virus, which is a type of coronavirus. It is true that coronaviruses have been known for some time, but the specific variant responsible for COVID-19 emerged in late 2019.

2. Influenza, or the flu, is caused by different types of influenza viruses. The 1918 flu pandemic was caused by the H1N1 influenza A virus, and since then, multiple strains of influenza A and B viruses have circulated worldwide.

Now, let's address the differences in vaccine effectiveness:

1. Novelty and research focus: The development of vaccines for COVID-19 saw unprecedented global attention and resources. As COVID-19 was declared a pandemic, the scientific community and governments around the world poured immense efforts and funding into vaccine development. This intense focus allowed for the rapid development of multiple vaccines using innovative technologies like mRNA vaccines (e.g., Pfizer-BioNTech, Moderna) and viral vector vaccines (e.g., Oxford-AstraZeneca, Johnson & Johnson). On the other hand, flu vaccines have been around for many decades, and while they have been updated yearly to match circulating strains, the development of a universal flu vaccine has proven challenging due to the ever-changing nature of influenza viruses.

2. Antigenic variability: Influenza viruses are known for their antigenic variability, which means they undergo frequent genetic changes (mutations). This leads to the emergence of new strains, making it necessary to update flu vaccines annually to match the most prevalent strains in circulation. In contrast, SARS-CoV-2, the virus that causes COVID-19, has shown less variability in its spike protein, the target of many COVID-19 vaccines. While new variants of SARS-CoV-2 have emerged, the existing vaccines have still shown effectiveness against severe disease, even if some may require periodic updates or booster shots to address new variants.

Regarding the prospect of a "universal flu vaccine," researchers have been working on developing one for many years. The idea is to create a vaccine that targets a conserved part of the influenza virus that does not change as rapidly as the surface proteins targeted by current flu vaccines. A successful universal flu vaccine would eliminate the need for annual updates and potentially provide long-lasting immunity against multiple influenza strains.

While progress has been made, developing a universal flu vaccine has proven to be a complex scientific challenge. Influenza viruses are highly adaptable, and finding a stable and broadly protective target has been difficult. Nevertheless, ongoing research gives hope that one day, a universal flu vaccine may become a reality, offering broader and longer-lasting protection against influenza strains. It is essential to continue supporting scientific research to combat both COVID-19 and influenza effectively.