Welcome to the Nutrition Facts Podcast. I'm your host, Dr. Michael Greger. Many of us are feeling

helpless in the face of the current pandemic, but the good news is there are things we can do right now

to reduce our risk of falling seriously ill and dying from COVID-19 and preventing even greater

infectious disease threats in the future. What should we expect in the coming months and years with

SARS-CoV-2? Let's look at the facts. Though the common cold coronaviruses follow a seasonal pattern

like the flu peaking every winter, there are other respiratory viral infections that peep in the

spring or the summer. In fact, MERS coronavirus, the last deadly coronavirus to cause an epidemic,

peaked in August in the sweltering heat and blistering sun of the Arabian Peninsula.

The mechanisms underlying the seasonality of viral respiratory infections remains a

subject of scientific debate as likely a combination of factors involving the virus itself, for example,

viral viability at different temperatures and humidity, host immunity, such as vitamin D status

and the drying of our airways, and host behavior like the crowding of susceptible individuals indoors.

However, the near-universal susceptibility to novel pandemic viruses may supersede these seasonal

factors. All the recent flu pandemics emerged in the spring or summer months. Those secondary waves

did tend to hit during the following winter. Even if the contagiousness of the COVID-19 virus drops

this summer in the northern hemisphere due to warmer weather weather, it is not expected to make a

large dent in the pandemic curve. What would stop the pandemic is herd immunity, having a

critical portion of the populace immune to the virus. An infection can only burn through a

population if there are enough susceptible individuals for the viral sparks to jump from one person

to the next. Immune individuals who can't get or transmit the virus act as fire breaks to slow

the spread or like control rods in a nuclear reactor to break the chains of transmission.

Ideally, this is accomplished through mass vaccination. Vaccines are a way to fight fire with fire

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