The Daily Dose: Herd immunity to COVID-19 via vaccination is possible but difficult.

A recent study analyzed the percentage of a population that would need to be vaccinated in order to achieve herd immunity. Their findings were sobering. For an ideal scenario where a single infection proffers life-long immunity, the researchers crunched the numbers, so to speak. “Given an R0 value before lockdowns in most countries of between 2·5 to 3·5, we estimate the herd immunity required is about 60–72%. If the proportional vaccine efficacy, ε, is considered, the simple expression for pc becomes [1 – 1 / R0] / ε. If we assume ε is 0·8 (80%), then the herd immunity required becomes 75–90% for the defined range of R0 values. For lower efficacies, the entire population would have to be immunised. These overall estimates ignore heterogeneities that can make these figures lower or higher in specific locations.” If immunity is short lived, things get much more complicated. If you also factor in vaccine hesitancy and full-on anti-vaxxers, sobering turns into depressing. Basically, all bets are off.

While we’re on the topic of COVID-19 vaccines, a separate study surveyed the general population regarding whether they would get vaccinated once a drug is available. Their findings don’t bode well. Per Reuters, “Conspiracy theories and misinformation fuel mistrust in vaccines and could push levels that potential COVID-19 vaccines are taken in the United States and Britain below the rates needed to protect communities against the disease, a study found on Thursday.” It looks like the worst case scenarios of the previously mentioned study regarding herd immunity is likely to happen.

On a lighter note… A recent study in PLOS Biology investigates the relationship between symbiotic, glow-in-the-dark biology and certain squids. Their findings elucidate some of the metabolic and genetic changes that occur between the two. “We report here that the bacterial sRNA SsrA plays an essential role in the light-organ symbiosis between Vibrio fischeri and the squid Euprymna scolopes. The symbionts load SsrA into outer membrane vesicles, which are transported specifically into the epithelial cells surrounding the symbiont population in the light organ.” Somewhat expectedly, the squid’s immune system experienced a discernable uptick, presumably to maintain its health while still enjoying the benefits from the bacteria.

Vitamins are everywhere. Entire chains of stores are dedicated to them. Yet, there has never been definitive proof that taking products like multivitamins actually improve the health of the persons taking them. A study in the British Medical Journal muddies the water further. “Nevertheless, the lack of any difference in the health outcomes assessed is in line with other studies indicating that multivitamin/mineral supplements don’t improve overall health in the general adult population, say the researchers. They put forward two possible explanations for their findings: either regular users of these supplements simply believe they work and that they confer health benefits in the absence of hard evidence to that effect, or they are just inherently more positive about their personal health, irrespective of their supplement use.” Considering how massive the health supplements industry is, the team’s findings certainly give reason to pause.

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