One good reason for vaccinations, is that if a large percentage of persons are vaccinated, it keeps the disease from spreading to those that are not vaccinated, including those exempt because they are already weak or sick.

“…most influenza vaccinations have short-lived efficacy and narrow protection” quote from https://asm.org/Articles/2019/August/A-Universal-Influenza-Vaccine-How-Close-Are-We

The immune system maintenance of previous antibodies can diminish its effectiveness at creating new antibodies towards a new viral variant or strain, a concept known as Original Antigenic Sin, or the Hoskins Effect. There is a “propensity of the body's immune system to preferentially utilize immunological memory based on a previous infection when a second slightly different version of that foreign pathogen (e.g. a virus or bacterium) is encountered”. Further related research: Cobey and Hensley 2017 Vatti et al 2017 Kim et al 2012 Eroshenko et al 2020.

If this is true, then vaccinations are a terrible idea? It seems so, if the virus, such as influenza, exhibits antigenic drift.

Vaccinations are at best 70% effective for the strain in question, and some years have been as bad as 50%. So if it is 50% effective, and the other 50% you are worse off because your immune system is not as effective, then the vaccine was definitely a bad idea.

Flu vaccine attitudes abroad differ from U.S.

Vaccines are poorly tested for safety and efficacy: https://www.bmj.com/content/371/bmj.m4037

Due to financial Conflict of Interest (COI), industry will more than likely ignore science.

Seriously, How Deadly Is Measles? by Dr. Nathan Boonstra, November 29, 2017

How many people were dying from measles, when there was no vaccine? So thankfully, Dr. Nathan Boonstra did the work for me, to find a death rate for people who contract measles: approximately 0.2%, or 2 deaths per 1000 cases of measles. Measles cases is said to have been 3 to 4 million a year 1 2. So about 7000 deaths per year. Sure, the population was less back then, but medical care has also improved.

In history, for isolated populations such as Hawaii, the death rate could be as bad as 20% (check reference as it's wikipedia).

I found this research article: Deaths following vaccination: What does the evidence show? They didn't get to the point in the abstract. Trying to dig through the results was daunting, so I looked for something easier.

“From January 2000 to December 2015, 104 deaths were reported to VAERS following the administration of one of the four measles vaccines.” ballotpedia.org 104 deaths happened after administration of measles vaccination, as reported by doctors, but some scientists refuse to use this data, because they say that just because the death happened after the vaccination, doesn't mean the vaccine was the cause of death. Did the doctors believe the vaccine was the cause of death? Or was it just a matter of chance that the subjects had a vaccine before dying of another cause? Not sure.

In any case, that's 104 deaths over 16 years, or 6.5 deaths per year. 6.5 deaths per year from vaccines is lots lots better than 7000 deaths per year from measles.

1 / 20,000 persons have a serious adverse event to a measles vaccine Spencer et al 2017, or 0.005%

According to the CDC: “In the decade before 1963 when a vaccine became available, nearly all children got measles by the time they were 15 years of age.”

“About 1 child out of every 1,000 who get measles will develop encephalitis (swelling of the brain) that can lead to convulsions and can leave the child deaf or with intellectual disability.” cdc.gov

At least according to the data above, for measles, vaccines are well worth it. What did people think of measles, back in the day? An answer on Quora by Estelle Winwoode: “No, measles wasn’t feared, it was expected. Everyone went through it, just once, then were known to be immune for life. If you were reasonably healthy and well nourished (vitamin A repletion is protective) the measles wouldn’t usually be much of a problem, also, people were familiar with the illness and generally knew how to nurse their children through it.”

Two more good responses on quora:
https://www.quora.com/What-is-the-chance-of-dying-after-contracting-measles-as-compared-with-influenza/answer/Luc-De-Mestre
https://www.quora.com/What-is-the-chance-of-dying-after-contracting-measles-as-compared-with-influenza/answer/Kelly-M-Bray

While the odds of people dying from a case of measles or flu are roughly the same, 90% of people who die from the flu are over the age of 65.

OMG. This one looks horrible. Shoot me up.

“The study authors noted that the World Health Organization recommends only a single adult booster vaccination during military service or when a woman becomes pregnant for the first time. The United Kingdom and some other countries recommend no adult booster shots at all.” source

Many people have issues with vaccine ingredients:
Addressing Parents’ Concerns: Do Vaccines Contain Harmful Preservatives, Adjuvants, Additives, or Residuals?, Offit and Jew 2003
What Goes into a Vaccine, publichealth.org 2020

https://www.macleans.ca/society/health/what-cuba-can-teach-canada-about-vaccines

“According to the World Health Organization (WHO)’s 2014 global summary on vaccine-preventable diseases and academic studies, Cuba has not had a single reported case of measles since 1993, nor rubella since 1989. Five cases of mumps have been reported since 2000; the last one was in 2010. And pertussis hasn’t been reported since 1994. In contrast, Canada has had 2,203 cases of measles, at least 1,529 cases of mumps, and 21,292 cases of pertussis reported since 1990.”

I hope with advances in molecular biology and virology, that vaccines become safer and viruses that are pathogens are completely eradicated. But are all viruses pathogens? We have evolved coexisting with microbes, and many are beneficial for our existence. There are more bacterial cells in the human body than there are human cells. Recommended reading: I Contain Multitudes, by Ed Yong. Perhaps the same is true for strains of viruses.