Vaccine Safety & Efficacy: As claimed?

Background.

Stage 3 Covid-19 vaccine trials produced an efficacy of 95% for the Pfizer/BioNTech vaccine, while the trials for the AstraZeneca vaccine produced result of 70% or 62%. Yet when full data is analysed, given the difference in how the trails were conducted, there is no concrete proof of which vaccine is more effective. The trials were different, and the AstraZeneca vaccine could also show 95% in a trial conducted the same way as the trial for the Pfizer/BioNTech vaccine. Confusing? Welcome to the complex world of vaccines for Covid-19.

What is a Virus?

It is even debatable whether viruses are alive or not. Some special viruses have more of the traits of life than others, but SARS-Cov2 does not. A virus is like a set of instructions within an envelope. It is not the envelop that makes you ill, it is following the instructions in the envelope that makes you ill. The instructions tell your cells, make another envelope that contains these instructions and place a copy of these instructions inside, that is all the virus is. The virus does not eat food or consume energy, and cannot itself make its own copy of itself.

Two Ways Covid-19 And Other Viruses Harm Us.

As explained, a virus is like a set of instructions that hijacks infected cells, and gets those cells to help produce copies of the virus. This causes two problems:

Infected, or “hijacked” cells and distracted from their original function, that reduces the number of cells tackling their normal task. With respiratory virus, this results in a reduction in the number of cells working to oxygenate our blood.
The immune system must target infected cells in order to stop the virus spreading, but the infected cells are cells of our own body, so the immune system springs into action against cells in the body of the infected person.

Problem number 1 is somewhat obvious, but problem number 2 can be also be a significant problem with many affects from disease being consequences of our own immune systems. Some viruses have a higher mortality amongst young healthy people with the strongest immune, as with some viruses it is the immune reaction doing the most damage as it attacks infected cells.

Another hypothesis suggests that the high mortality of young adults may be due to an overactive immune response (i.e., cytokine storm) at the height of immunocompetency [24]. Inoculating monkeys with the reconstructed 1918 influenza H1N1 virus, Kobasa et al. [25] attributed its unprecedented lethality to an “aberrant innate immune” response. Infected animals mounted a dysregulated antiviral response that was not only insufficient for protection but ultimately caused a highly pathogenic respiratory infection that killed them.
National Centre For Biotechnology Information.

The above quote discusses how it can be the immune response that become lethal rather than the virus itself, even though it was concluded this was not necessarily significant in the 1918 pandemic. Again with Covid-19, it is clear that immune response is not the main health problem, it can still be fatal in a small number of cases, particularly in young healthy adults.

Vaccines Don’t Fight the Virus, You Do.

Human immune systems fight the virus, not vaccines. Vaccines just get you in shape and prepared for the fight. Vaccines contain no element of treatment for the virus, in fact vaccines more resemble the virus itself, than resemble a cure. The virus hijacks some of our own cells, and gets them to help produce copies of the virus. What the vaccine does is give a persons immune system an ‘early look’ at proteins the virus gets our cells to make, so the persons immune system identifies sites of the protein and starts fighting blocking hijacked cells from producing that protein very quickly, rather than letting the amount of virus increase while the immune system is even recognising their is a fight. Without immunity, it is like giving away the first few rounds of the fight, while getting ready for the fight.

As all fighting is done by the persons immune system, if a persons immune system is incapable of fighting the virus, the vaccine is of no use. The efficacy of a vaccine, is limited by the ability of a persons’ immune system to fight the virus. If there the persons immune system is unable to win the fight even if ‘ready’ even before the virus arrives, either because their immune system is not strong or because the virus is super strong, then being ‘ready’ will not help.

Since all effectiveness in fighting the virus comes from the human immune system, different results from different vaccines come down to so any variation in the performance of vaccines, all comes down to:

different levels of ‘readiness’ resulting from the vaccine
or a variation in the percentage of people developing ‘readiness’

How much of an ‘head start’ in fighting a virus does a vaccine provide? The best advantage a vaccine can give is that, for 100% of people vaccinated, the immune system is able to start fighting the virus immediately. In theory there could be several vaccines that all ‘ready’ the immune system to its full potential.

Can we agree on when an infection becomes a ‘case‘?

Comparing cases following vaccination is problematic, since there is no agreed definition of a ‘case’, and different trials used different definitions.

Technically, Covid-19 is the name of the disease the results from the SARS-CoV-2 virus. Simple, or at least it sounds simple. When the virus spreads within the body, and the immune system is needed to fight spread, that is the disease. Except, things do not always follow a consistent script. Some people are asymptomatic, yet can still infect others. Are such people cases, and have the disease? Or do they just have the virus, given the fight goes unnoticed? Others get ‘long Covid‘, without having the initial symptoms, and those initial symptoms themselves are are widely varied. In essence, there is no one simple clear definition of when a person has the disease ‘disease’, because ‘the fight’ takes place in different ways and even in different organs of the body, with a variety of outcomes from being infected. The severity of resulting illness, even in people of similar age and underlying health, ranges completely from ‘no noticeable effects at all’ through to death. All this makes the Covid-19 disease rather unspecific, resulting in even some official publications making no clear distinction between the virus, and the disease. In the end, there is no definition of exactly what should counts as a case of Covid-19.

At one extreme, if the the virus invades just one cell of person, it could be considered an infection, yet at that point would be impossible to detect the person is infected. In reality, there is no universal standard for a number of cells a virus needs to infect before a person is considered infected.

So each trial must set its own standards on what constitutes a ‘case’ of Covid-19.

What does ‘infected‘ mean?

It may seem that although there are varying definitions of when an infection with the SAR-Cov2 virus becomes a case of Covid-19, at least the definition of an infection would be unambiguous. Sadly, again, not so simple.

Here are the potential steps:

virus fragments get into a persons body.
virus fragments in the body invade cells
invaded cells reproduce the virus
reproduced virus cells infect cells faster than they die, so infection increases (R₀>1)
infection reaches a level that produces a positive test for the virus.

Any one of these steps could be described as ‘infection’. Virus fragments exist in protein droplets that float in the air, and since no vaccine can prevent these entering the human body, no vaccine could prevent infection under this definition. A clear definition would be a positive test, but it is known that a person will normally test negative for the first few days following ‘infection’, and can even be infectious while testing negative. This makes defining infection as when the level of virus is detectable by a test, also problematic to say the least. In the end, different people use different, and often imprecise definitions, largely because no precise definition is measurable.

If cases and infections are dependent on interpretation, What is ‘Immunity‘?

Immunity sounds very definite. Once vaccinated, if the vaccination is effective it would seem you should be immune to the virus, and therefore will not be infected afterwards. Yet, as already discussed, there is not definitive definition of how many cells need to be infected before you are considered ‘infected’.

In fact there are different levels of immunity, but necessarily definite answers for any other them:

Immunity from any infection from the disease by all definitions of ‘infected’.
Immunity from becoming a carrier of the disease.
Immunity from a symptomatic case of the disease,
Immunity from a serious case of the disease.

Immunity from any infection from the disease by all definitions of ‘infected’ .

This is actually almost impossible to achieve, as there have to be infected cells before the immune system can even respond. The best case is that there is no infection of any significance. So, the vaccines will not be achieving absolution protection against any infection at all.

Immunity from becoming a carrier of the disease.

While for many diseases a person needs to be symptomatic to infect others, this is not always the case. With both measles and Covid-19, asymptomatic spread is possible, and as proven by ‘Typhoid Mary’, individuals can be asymptomatic spreader even if this is not always the case.

It seems clear that with Covid-19, being vaccinated will not prevent people becoming carriers, and thus will not completely eliminate spread, but it should reduce spread. Whether the reduction of spread is sufficient to result in herd immunity is not yet clear, and may be dependant on what stain of the virus, as well as other factors such as season and population density.

Immunity from a symptomatic case of the disease,

Estimates for the effectiveness of current vaccines in preventing cases of Covid-19 of sufficient severity to result in symptoms range from 50% though to 95%. Not perfect, and suggesting prevention of spread could be low.

Immunity from a serious case of the disease.

This is where some current vaccines produce impressive results, with as few as less than 1% of ‘infections’ resulting in fully vaccinated developing a severe infection. Note this is “as few as”, and results may vary with a whole range of factors and the optimum result may be rarely achieved, or achieved only for a small window of time following vaccination.

Vaccine Safety

How Vaccines Work: The Core Principle.

Vaccine is derived from the Latin word for cow, because the first vaccine was from the cowpox virus, which to the human immune system, looks like smallpox, but is in fact relatively harmless. This the the core principle for vaccines. The vaccine should:

Look to the immune system just like the cause of the disease being vaccinated against.
Be itself relatively harmless.

Note that step 2 does not mean totally harmless, as achieving step 1 successfully will trigger an immune response, and the immune system itself is not totally harmless. So step 2 only ensures no additional risks over and above those that inherently arise from producing an immune response.

Vaccines and Side Effects.

This page started in response to being asked if am I worried about long term side effects from vaccines, prompting me explore what I could discover.

Side effects for a vaccine are anything other than the primary goal, which is the development of immunity, and include adverse effects from having an immune response, as well as to any reactiong to the vaccine itself.

I have heard quotes of things like, “if there is a less than 1 in 100,000 chance of a bad reaction to the vaccine, and perhaps a 1 in a 1,000 chance of dying from Covid-19, I would take the vaccine!”. Except, already in some places, there may be need be no certainty of getting infected Covid-19 at all, but there is certainty you will get the vaccine if you get vaccinated. If more and more countries start to reduce the risk from Covid-19, the balance of risk from vaccination become more critical. It is easy to imagine a post-pandemic world where people no longer see Covid-19 as a risk provided their vaccinations are up to date. This could leave humanity a far smaller health problem in the form of the reactions to vaccines. Far better than Covid-19, but still a step back from the pre-Covid-19 world. This would also be a far more problematic situation, as the major problem in this situation would be deliberate.

The payload or ‘cargo’:
- Some form of remnant of the target virus itself, or instructions to cells to build a fragment
The Delivery mechanism:
- Generally either a disabled substitute host virus, or an mRNA delivery mechanism

The design is that nothing of vaccine itself remain in the human body within around 2 weeks. The vaccine has a very short mission, trigger the human bodies immune response to Sar s -COV2. In theory, nothing remains in the body other than the bodies own immune response at the end of the two weeks. Unlike the actual virus, nothing in the vaccine is capable of reproducing, even within host cells.

There are two types of possible side effects to vaccination:

Adverse reactions from the persons own immune system to detecting something that looks like the virus, “the cargo” or “payload”.
An adverse reactions to the delivery mechanism or ‘carrier’ of what looks like the virus.

The first adverse reaction is not always avoidable, as without the immune response, there will not be immunity. If adverse reactions are too significant, than a vaccine is unworkable, and the best that can be done is to vary the way or speed the immune system is exposed to the “payload” which may reduce the adverse effects of the immune system activating, but the nature of the immune system is that adverse effects from an immune response can rarely be totally eliminated.

The second problem is avoidable, find another delivery mechanism or carrier. Unlike the immune response effects, if a vaccine gets through trials with negative effects from the carrier in the short term, then someone is negligent. Further, if the carrier is still present in a person after a month, then this should also be considered a failure, and if the carrier is gone, it is unlikely to have long term effects.

Short Term Side Effects.

How long is short term? If it is less than 3 months, than most short term side effect should be able to be detected within vaccine trials. Obviously as more people are vaccinated, rare effects no showing in the trial may emerge, but at least these must be rare if the trials were well conducted.

Long Term.

So far, there is ample data on short term reactions to the vaccine, and the risks are low.

But what about long term?

There are studies that rule out a long term reaction to either type of delivery mechanism, as both delivery mechanism types have been studied for decades, even that used with mRNA. The new component is the immune reaction to the ‘cargo’. We can’t rule out long term effects from the bodies own primed immune system, with the only certainty being that this reaction can be no greater than from being infected with the virus. Further, since the combination of vaccine, followed by infection with the virus, produces a far milder case than experienced by unvaccinated people, if there is any likelihood of being infected with Covid-19, then it is better to be vaccinated than not be vaccinated.

So, in summary, the risk seems extremely low, but why take any risk, if it can be avoided? If vaccination doesn’t result in herd immunity, and the virus is then eradicated, then why bother being vaccinated?

Of course, as a “catch 22” if vaccination does not result in herd immunity, the virus will keep spreading so vaccination makes sense as the result of being infected with the virus itself is significant.

A problem is that we just do not know. If, as data suggests, vaccination reduces spread, than either vaccination alone, or in conjunction with some other measures does produce herd immunity. Except, if everyone took this approach, and avoided vaccination, then there cannot be herd immunity. In practice, for children, who have the longest time to worry about long term effects, and the least reason to be vaccinated at this time, it could make sense to wait and see what is happening in terms of herd immunity before vaccination.

However, given the sheer total amount of the virus circulating world wide, a vaccination program resulting in eradication of the virus is no more likely that a new strain of the virus emerging. While it would be better if all countries of the world had followed the examples set by those eliminating community spread and made vaccines redundant, that is not the world in which we live. This make vaccination for all a likely necessity.

No, Vaccines Can’t Change Your DNA.

There are many myths circulating about vaccines, and some of this is driven by social media driven conspiracy theories.

A quick search on mRNA reveal diagrams of mRNA produced in the nucleus of Eukaryote cells…which are our cells! It can seem from a quick read, that these vaccines require our cell nuclei to produce the mRNA! Won’t that mean changing our DNA?

This explores why it looks like that, and why the vaccines cannot change your DNA. The first things that mRNA as discussed in many resources, it not talking about vaccines, but mRNA our cells produce naturally. mRNA is not all about vaccines.

I had this vague idea that animals have DNA, and viruses have RNA. In fact animals have both DNA and RNA, while viruses such as SARS-Cov2 RNA, but no DNA, and may not even considered to be ‘life’. Looking deeper, it turns out that while our genetic code is in our DNA, our bodies also generate RNA, and these diagrams of cells producing RNA and mRNA are what happens with our existing cells, all the time, no vaccine required. Our own cells produce mRNA, and the mRNA produced in the nuclei of our cells, does not then get into the nuclei of other cells. mRNA is a type of messenger our cells make, and that we already produce.

An mRNA vaccine is a messenger using mRNA (messenger RNA), similar to mRNA our cells make naturally inside our bodies, but in this case made in a lab. As mRNA breaks down naturally very quickly, these mRNA vaccines must be kept extremely cold to slow them breaking down long enough to still work. Once injected, the messenger mRNA tells cells to make a protein as described in the RNA, and that mRNA quickly breaks down, so only a limited amount of the protein as described will ever be made in your body. The mRNA does not ever get to interact with your own DNA.

The virus infects cells and gives them instructions to produce proteins and the virus needs carry a copy of their genetic code, and infect other cells with that code, and to place a copy of the virus inside the proteins. The mRNA vaccine has a simpler role, just reduced instructions telling your cells to produce some of the spike protein part of the virus, because it is this spike protein that triggers the bodies immune response.

So, no mRNA vaccines do not change your DNA to get your DNA to produce the right mRNA, they are just a supply of mRNA that your body’s own cells did not produce, and as a result, get some of your cells to make some protein they would not normally make. Niether the mRNA, or the proteins last more than a few days in your body, but that is long enough for your body to treat that new protein as ‘foreign’, and make antibodies against it.

Comparing Vaccine Trials

How A Trial Should Work.

Vaccine trials normally all:

divide participants randomly into
1. a placebo group
2. and a live vaccine group
include a system for determining if participants get ‘Covid-19’

Variables between trial are:

what age group and spread of ages within age brackets participate in the trial?
what is the prevalence of Covid-19 within the community(ies) of the participants
what is the behaviour (lock-downs, social distancing, group gatherings etc) of particpants
what virus strains are present during the trial
what standard is in use to determine ‘a case’

Provided all of these factors are the same for both groups, which will be in selection between placebo and live groups is random, there the trial will be valid. However, different trials with different variables even with the same vaccine may yield different results.

Different Results?

How were Astra/Pfizer trials different?

Information on all variables is difficult to obtain. However, one key difference between the trials is the standard for deciding what constitutes an infection.

Very different!

In clinical trials, the Pfizer vaccine was found to be 95 per cent effective at reducing disease. But whether it stopped people from getting infected in the first place isn’t yet known — because it wasn’t measured.
Larisa Labzin, an immunologist at the University of Queensland, says it’s possible there were people in the Pfizer trial who received the vaccine, got infected with COVID-19, but didn’t develop any symptoms.
They wouldn’t have been identified, nor included in Pfizer’s analysis, because researchers were specifically looking at whether the vaccine stopped or reduced the severity of COVID-19 symptoms — not whether the vaccine prevented infection in the first place.
ABC

Now compare this with:

“Whereas in the Oxford-AstraZeneca trials, [the researchers] made all the participants do a COVID test every week,” Dr Labzin says.
“The idea was to pick up whether the vaccine would prevent infection as well.”
The University of Oxford study took weekly nose and throat swabs from a group of UK volunteers, regardless of whether they showed symptoms or not, says Sharon Lewin, infectious diseases expert and director of the Doherty Institute, who was not involved in the work.
The researchers note that they did not set out to specifically measure disease transmission — rather, they focused more on finding the optimal time between doses.
But they did use the presence of virus on a swab as a proxy for the likelihood that the person could pass the disease on to someone else.
They found a 67 per cent reduction in positive swabs among people who received a single dose of the two-jab Oxford-AstraZeneca regime.
This does not mean transmission was reduced by two-thirds, Professor Lewin says.
“But we now know that the amount of virus in the nose is associated with transmission — more virus in the nose, higher likelihood for transmission,” she says.
ABC

In summary:

The Pfizer vaccine trial was only looking at reducing disease, the AstraZeneca trail was looking at transmission of the virus even when disease was reduced.

I suggest it is possible the Pfizer vaccine may have recorded the exact same results as the AstraZeneca vaccine in trialled in the exact same manner. Not certain, but certainly possible.

Why are both trials valid?

An initial reaction to discovering AstraZeneca trials tested participants each week, while Pfizer trials did not could be: ‘Of course Pfizer detected less cases!’. However, Pfizer would have detected more less cases in both groups: the live vaccine group and the placebo group.

The Pfizer approach is also valid, because the same ‘lower rate of detection’ would have been in place for all participants. The 95% efficacy means 20 times less infections detected with the live vaccine group. There is a genuine 20x reduction in the number of people who showed sufficient symptoms to be tested.

So scientific method is followed, and that makes both trials equally acceptable.

However, there were not directly comparable, as they measured different criteria. So is 20x less people showing sufficient symptoms to get tested, more impressive than 3x less people testing positive when everyone gets tested? Unless vaccines are far more effective at reducing cases to asymptomatic cases, they yes it would be, however that is exactly what other evidence suggests. Neither trial reported any case of severe Covid-19 in the live vaccine group.

Vaccines efficacy: Yes, No, and Maybe

For data updated from real world up to August 2021 see here

‘Yes’: Vaccines Do Well On The Original Mission, Saving Lives.

The original goal for vaccines was to save lives and prevent severe disease. The vaccines are most effective, highest ‘have highest efficacy’ in achieving this goal. Reports are that even in the most vulnerable age group, just a single dose of vaccine achieves an over 80 reduction in hospital admissions, which is exceeding the original targets for a vaccine.

Even in the worst trial results, there is no evidence of vaccines failing to prevent severe cases of Covid-19, in fact, to the contrary, even against the most challenging strain of the virus so far, vaccines still save lives.

But experts say that although less effective against the South African variant, the current vaccines are likely to save your life if you become infected with it.
In a recent trial, the Johnson & Johnson vaccine, for example, was 85% effective at preventing severe illness and hospitalization — no matter the variant.
South African COVID variant can chip away at vaccine efficacy — but the vaccine can still save your life

The article quoted above noted that when considering overall efficacy, the Johnson & Johnson vaccine was tested as 57% effective against the South African variant, but 85% effecting at preventing severe disease requiring hospitalisation. No specific trial against mild infection is quoted, but as with AstraZeneca vaccine, such a trial may show even lower efficacy.

The original mission of vaccines was to reduce deaths and severe disease resulting in overloaded hospitals. This goal appears to have been met.

No, Vaccines Do Not Achieve Full Immunity From Spread.

In summary, vaccines do not enable ‘immunity passports’ that confirm the bearer as presenting no risk of infecting others. Reduced risk maybe, but not zero risk, certainly not.

I am not aware of any vaccine trial confirming any vaccine is particularly effective against low levels of infection. This does not mean vaccines, or at least some vaccines, are not quite effective against all levels of infections, but all data suggests no vaccine prevents all levels of infection. Trials with highest efficacy (e.g. 90% or 95%) were limited to the original variant and did not test for lower levels of infection that may still enable transmission.

Clearly, all data so far means it is still possible for any vaccinated person to still spread the virus. The risk of a vaccinated person spreading the virus may be reduced, and perhaps even significantly reduced, but it is clearly not eliminated.

This means giving priority to vaccinated people can make sense, but allowing vaccinated people to skip quarantines and then enter areas where the consequence of introducing the virus are significant does not make sense.

Maybe: It Unclear, But Unlikely, Vaccines Reduce Spread Sufficiently for Herd Immunity.

A big, and as yet unanswered question, is can vaccinations sufficiently reduce spread to produce herd immunity? If vaccinations can achieve this, it could mean the end of the pandemic. Israel is the best test so far, and there are some positive results, but these results do not suggest Israel is ready to risk the arrival of variants from South Africa or Brazil.

If within a vaccinated population, the spread factor or R0, is reduced from the current 2.5-3.5 range to less than 1.0, then vaccinating a population will end the outbreak. This goal looks possible, but we are not there yet and the road is rocky, with the virus having ample time, and huge population of copies of the virus, to evolve in order to remain a threat.

Herd immunity is dependant on ‘immunity from becoming a carrier of the disease‘, and this data is not yet established (in February 2021).

I plan to update with news on the data from Israel at some point (plan-update).

Covid-19 soon like the ‘common cold’?

How?

So far, vaccines reduce the severity of cases of Covid-19, to potentially to a level of severity no less debilitating than influenza, if not the common cold. I say potentially, because we do not yet have data on the reduction of ‘lon g -covid‘, but as this results from Covid-19 infections in other parts of the body that the respiratory system, there may be a similar reduction in threat from vaccination.

However, vaccines may not stop the spread.

So if everyone is vaccinated, getting infected may be very common, and the virus could keep circulating, just without an ‘unacceptable” level of hospitalisations and deaths. Of course, that may require adjustment as to what is considered acceptable, and that is with potentially periodic immunity “boosts”.

A sleeping giant, or a tamed lion?

A sleeping giant is not harmless, as eventually the giant will wake. How about a tamed lion, which could remain tamed? Tamed is not harmless either. A lion that is tamed to behave as a pussy cat still presents a threat because of its greater capacity for damage if things go wrong. Covid-19 tamed by vaccines to be as harmless as flu or even the common cold, still presents a threat because because of its greater capacity for damage if things go wrong. Living with a lion is never really as safe as living with a cat, even if the lion has been tamed.

If you are wearing a bullet proof suit, then bullets could hurt no more than paintball shots do when wearing normal clothes. However, even if wearing bullet proof clothes, it is still recommended to treat bullet file with caution. To tread carefully because the bullet proof clothing may reduce the bullets to being a sleeping giant, but they are still a giant danger.

Could it wake up, or break training?

While the virus still spreads, it can mutate. Starting from an already dangerous starting point, it is still better to eradicate spread, (as per current situation in countries like Australia, New Zealand, Taiwan etc), than to open borders and let the virus spread.

Scorecard as of Feb 2021

AstraZeneca vs Pfizer/BionTech – no proven difference beyond PR

As to one vaccine being better than another, there is simply no clear evidence yet. What is clear is that they all can save lives, which will help unless zealots of vaccine passports worsen the problem.

Vaccines Ending Covid-19: Not yet.

While in the US, the ‘wave’ did subside as vaccination rates climes, but he wave climbed in advance of the vaccinations, not as a result of the vaccinations. In Israel, signs are positive, but it is certainly not clear that vaccinations alone can end the pandemic.

Vaccines saving lives: Winner- vaccines.

While vaccines may not yet end the pandemic, the certainly reduce fatalities.

Vaccines making ‘vaccines passports’ a good idea: definitely not!

Vaccine passports are emerging as one of the main threats to ending the pandemic. Prematurely declaring threats as ‘over’ has been one of the main problems so far, and these could be just another step on that path. If people act as though once vaccinated the threat has passed, then the virus will continue to multiply and very like, evolve.

Conclusion

Do Get Vaccinated: Vaccines save lives – but proceed with caution.

I do not mean caution in regard to being vaccinated. All the evidence, and it is compelling evidence, is that being vaccinated is effective beyond what could have been expected in terms of providing protection against serious cases of Covid-19.

Further, there is no evidence of side effects that do not also result from infection, and as would be expected from what is effectively a cut down version of the virus, these effects are all things you would more likely experience or more seriously experience if infected with the real virus.

Don’t Blindly Trust ‘Vaccine Passports’.

If you get vaccinated, don’t then blindly believe you cannot infect others. If vaccinated people all drop all social distancing, we could have a new wave. Even someone safe from Covid-19, is not immune to all reasons they may needing a hospital that is not overcrowded.

If not vaccinated, still take precautions around those who are vaccinated. They are even less likely to show symptoms, but may still be infectious.

New Territory: Vaccines that do not prevent disease spreading?

In the past, vaccines have enabled us to eradicate diseases. Smallpox is largely eradicated. There are attempts to eradicate polio. Even with influenza, the role of asymptomatic spread is considered minor

However, we have found limited evidence to suggest the importance of such transmission. The role of asymptomatic or presymptomatic influenza-infected individuals in disease transmission may have been overestimated in recent
articles dealing with pandemic planning. More definitive influenza transmission studies are needed
Division of Infectious Diseases, Department of Medicine, Warren Alpert Medical School of Brown University, Providence, RI

And therefore with sufficient vaccinations, at least the strains of influenza addresses by vaccines could in theory be eradicated. As with the example of “Typhoid Mary” asymptomatic spread of disease is problematic, and it is this asymptomatic spread of Covid-19 that makes the disease such a problem. The result is that vaccinations, at least in their current form, may be unable to stop the disease spreading. Which means the risks of ‘long-Covid‘, and of more dangerous variations of the virus remain.