Post Reply - A new pandemic

NPJ Vaccines: Modeling the Impact of Early Vaccination in an Influenza Pandemic in the United States

While once thought of as a `once-in-a-generation' event, in my lifetime I've already experienced 4 legitimate pandemics (1957, 1968, 2009, 2020), 2 pseudo-pandemics (1977, 2003), and one `near-miss ' (1976).

Which brings us the question: is it better to have a less-well-matched vaccine earlier (at 3 months), or wait (6 months or more) for a well-matched vaccine?

It is not an easy question to answer, because there are so many unknown variables.  As the old saying goes, `If you've seen one pandemic . . . . you've seen one pandemic'.  The speed of transmission (R0), its place of origin, its virulence (CFR and Attack Rate), and even its impact on different age groups, all change the outcome. 

We've a study today that attempts to model the impact of early vs. late vaccination in a variety of pandemic scenarios, juggling virulence (moderate or severe), and vaccine effectiveness (high, moderate, or  low), in order to try to quantify the probable benefits. 

In order to keep all of this manageable the authors had to make a number of assumptions that may, or may not, hold true in the next pandemic; an origin in the Southern Hemisphere, a greater impact on older patients, and a single wave, etc.   

Vaccination from 3 months with a high, moderate, or low effectiveness vaccine would prevent ~95%, 84%, or 38% deaths post-vaccination, respectively, compared with 21%, 18%, and 8%, respectively following vaccination at 6 months, irrespective of pandemic severity.

While the pandemic curve would not be flattened from vaccination from 6 months, a moderate/high effectiveness vaccine could flatten the curve if administered from 3 months.

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This study uses a lot of epidemiological assumptions, which may (or may not) be a good fit for the next pandemic.  Much will also depend upon how society reacts to the next pandemic.  

• Will lockdowns be tolerated, or will people refuse masks and social distancing?   

• Assuming a vaccine could be produced in quantity in 3 months, would large segments of the public actually embrace it?  How much extra resistance against an mRNA vaccine? 

• How much tolerance would the public have for (real or imagined) vaccine side effects, particularly in a low VE jab?  

While I'm not particularly hopeful that an emergency vaccine of any VE can be produced and deployed within the first 3 months of a novel pandemic - in the event of a severe disease - this study strongly suggests that the earlier that can happen, the better.