How Soon Before We Cross the Line of Herd Immunity?

Herd immunity is just across the fence. We will see it this year.

Over one-half of the citizens of England have received at least one dose of the coronavirus vaccine. Is the United States almost there? Does that mean herd immunity is around the corner, or is there no visible light at the end of the tunnel?

Herd Immunity

https://bit.ly/3eWqGQo. One person infects another person, and that person infects another. That is how diseases are spread. It might be by breathing in disease particles into the lungs or maybe by touching a contaminated surface, or even intimate contact with another person.

Herd immunity is achieved when enough people have been infected, and acquired immunity and/or a high percent of people have been vaccinated against a specific pathogen. The disease cannot spread because there are no viable hosts to accept the bug. The disease withers away, not necessarily gone forever, but not actively infecting people.

Scientists use the term basic reproduction number, R0 (R-naught), to mathematically quantify a disease’s contagiousness, how fast it transfers from one person to another. It is the measure of secondary infections – a person you infect passes the disease to another person.

Each disease is different, as is each population demographic. Infections increase when R0 is greater than one and decrease when R0 is less than one. Last week, Houston had an R0 of 0.92. It had been below one for several days. This week, the R0 for Houston is 1.1. https://www.tmc.edu/coronavirus-updates/effective-reproduction-rate-for-harris-county/.

Each disease has a different R0. Measles, for example, has an R0 of around 15. One person will infect roughly fifteen people. To achieve herd immunity for an R0 of 15, 95% of the people would be vaccinated and have caught measles.

Once herd immunity is reached, it does not guarantee you are home-free. Personal protection is still required after herd immunity is achieved to allow the disease to wither away further.

The SARS-CoV-2 virus responsible for COVID-19 has an R0 of around 2.5. Approximately 65% of a population needs to have had the disease and been vaccinated to reduce the R0 below 1.0 fully. The disease cannot readily infect another person because they are not susceptible to that disease.

You might ask about variants because that is prevalent in our media today. Yes, people can catch the same basic disease with a slightly new twist. About 99% of people will survive contact with the more recent coronavirus variants because they had survived the virus or been vaccinated.

In the COVID-19 virus, the spikes on the outside of the viral molecule must contact and connect with the ACE2 (angiotensin-converting enzyme) receptor in your nose or lungs. Vaccines target the spike to stop the connection mechanism from transferring viral particles into your body.

Variants change the basic structure of the viral molecule. The spike contains over 1,000 amino acids arranged in a specific order. Changes occur to this structure as variants develop. However, the difference usually involves less than 5% of the amino acid arrangement, making the vaccine fully effective to reject the other 95% of the spike connection.

People with deficiencies of vitamin D3 tend to have higher rates and more severe symptoms when they contract COVID-19. Some specialists speculate that vitamin D3, as an ACE2 regulator, inhibits the viral spike from fusing with a host cell.

I started using a nasal spray available at CVS Pharmacy called Xlear. It has laboratory tests confirming that it blocks the ACE2 receptor and diminishes the viral connection and further infection. I use it every time I leave my home. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7645297/

United Kingdom Vaccine Program

https://abcnews.go.com/Health/wireStory/half-uk-adults-dose-covid-19-vaccine-76578243. Half the people in Britain over the age of 18 have received the first of their two doses of COVID-19 vaccine. United Kingdom’s goal is to have everyone immunized by the end of July.

UK R0

https://www.gov.uk/guidance/the-r-number-in-the-uk. Keeping with the topic of R0 and herd immunity, the current R0 in England is between 0.6 and 0.9 and continuing to decrease weekly. The average weekly decrease in R0 has been between 2 and 7 percent in all United Kingdom areas. Britain appears to be on the precipice of controlling the transmission of coronavirus.

United States Vaccination Program

https://covid.cdc.gov/covid-data-tracker/#vaccinations. Seventeen percent of Americans (over the age of 18) have had both doses of coronavirus vaccine. Thirty-one percent have had one dose. The numbers vary by demographic. Nearly 70% of older adults (over 65) have had one dose, and over 40% have had two doses.

We must add ten percent of Americans who survived the virus. That means the US has almost 30% of its population protected from the virus. The numbers vary by website. Some include COVID-19 survivors who also received a vaccination. Nearly two and a quarter million doses of coronavirus vaccine are given daily. Based on this alone, it will be August before 75% of Americans have achieved herd immunity.

Conclusion

R0 is not the only measure of the spread of disease. Personal protection offers insurance to individuals. Can you catch the virus a second time once you survived it or are vaccinated? Yes, however, it is more age-dependent, especially in those with challenged immune systems.

More vaccines are in the pipeline. My original forecast for herd immunity was September. I am still sticking by my estimate. Things happen that we do not plan for all the time. Even though the trend lines are declining for new cases, hospitalizations, and daily deaths, the assumption is that a new surge could develop quickly. Spring break is upon us. We will know more in a couple of weeks.

Live Longer & Enjoy Life! – Red O’Laughlin – RedOLaughlin.com

 


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