|FROM ||Ruben Safir
|SUBJECT ||Subject: [Hangout - NYLXS] Why Vaccines Are Essential to Herd Immunity
|Why Vaccines Are Essential to Herd Immunity
Why Vaccines Are Essential to Herd Immunity
Alberto Cervantes and Josh Ulick
An infectious disease like coronavirus, if left unchecked, can spread
rapidly through a community. Scientists use the transmission rate, or R0
number, to denote how many people a typical carrier of a disease may go
on to infect.
In the absence of control measures such as social distancing or mask
wearing, the novel coronavirus has an R0 number of between 2.5 and 3.0,
meaning the average carrier would infect between two and three people.
As those people go on to infect others, the disease can spread rapidly
through a community that hasnít been exposed to it before.
However, as more people contract the disease and gain some level of
immunity, the diseaseís spread will slow naturally.
When enough people become immune such that the whole community is
protected, itís called herd immunity. Herd immunity can sometimes occur
naturally from survivors of the disease within a population, but often
not without many deaths. Covid-19 has so far killed close to 200,000
people in the U.S. Epidemiologists believe only a small percentage of
the nation has been infected and developed some level of immunity.
The introduction of a vaccine can be the quickest, safest way of
creating herd immunity, since people can develop immunity without
getting the disease.
Scientists estimate that 60% to 70% of the population might need to gain
immunity to Covid-19 before herd immunity is reached. Thatís based on an
estimated R0 number of 2.5 to 3. Compare that with measles, a highly
contagious pathogen with an R0 number of 12 to 18 and a 90%-to-95% herd
Depending on how effective a vaccine is, it might not provide complete
immunity. In that case, more people might need to be vaccinated to reach
In New York City, an epicenter of the U.S. epidemic, some researchers
estimate 25% of the population has protective antibodies against
Covid-19. In other parts of the country, the rate could be far lower.
Waiting for 60% of the global population to gain natural immunity could
mean billions of infections and millions of deaths.
Vaccines work by exposing people to a disabled version, or component, of
a virus. This teaches the immune system to recognize the virus, so it
can later defend against it in the event of an actual infection.
About 170 Covid-19 vaccines are in development around the world,
according to the World Health Organization, each one promising to
protect people from the deadly coronavirus and allow them to go back to
work and school. A handful are starting or nearing the final stage of
The testing trials could provide some results as soon as the end of
October. The U.S. government plans to begin shipping any Covid-19
vaccines within 24 hours of a green light from regulators. Health
officials including Anthony Fauci, director of the National Institute of
Allergy and Infectious Diseases, have said that the vaccine likely wonít
be widely available until later in the year.
Write to Alberto Cervantes at Alberto.Cervantes-at-wsj.com
So many immigrant groups have swept through our town
that Brooklyn, like Atlantis, reaches mythological
proportions in the mind of the world - RI Safir 1998
DRM is THEFT - We are the STAKEHOLDERS - RI Safir 2002
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