Here is one Covid conspiracy theory; side-affects from the vaccines are very rare and should not stop you taking the vaccine. This particular conspiracy is promulgated by Britain’s NHS.
Any side effects are usually mild and should not last longer than a week, such as [then the page lists things like a sore arm]
More serious side effects, such as allergic reactions or blood clotting, are very rare. 
If and only if you follow a link on the above page will you find information about blood-clotting. This is what we have:
The MHRA is carrying out a detailed review of reports of an extremely rare blood clotting problem affecting a small number of people who had the Oxford/AstraZeneca vaccine. The COVID-19 vaccine can help stop you getting seriously ill or dying from COVID-19.
For people aged 40 or over and those with other health conditions, the benefits of being vaccinated with the Oxford/AstraZeneca vaccine outweigh any risk of clotting problems. For people under 40 without other health conditions, it’s preferable for you to have the Pfizer/BioNTech or Moderna vaccine instead of the Oxford/AstraZeneca vaccine. 
The above is the current information at 27 July 2021. It tries to present the blood-clotting problem with AstraZeneca as something which is being studied. In fact the truth is it is already firmly established that AstraZeneca carries a risk of causing serious blood-clotting events. I have had to search very hard indeed to find this information on the Internet. I cannot prove it but it looks to me like Google may be suppressing it. (For example the search autocomplete feature which is usually very responsive did not help at all; and most of the pages returned were out of date). However the fact is that AstraZeneca causes blood-clotting events in 1 in 100,000 people over 50. For those under 50 the rate is 2 per 100,000. 17% to 20% of these events are fatal. It also seems that a study has concluded that giving AstraZeneca to people in the age group 18-39 would cause more deaths than lives saved. We can extrapolate from this to say that in children the risks from the AstraZeneca vaccine far outweigh the risks. This information comes from an Irish newspaper  which is reporting a study by the European Centre for Disease Prevention and Control and information from the Irish HSE. These are the facts as they pertain to AstraZeneca.
I would not say that a 1 in 100,000 chance of a serious blood clotting event (in those aged over 50) which carries a 17% – 20% of being fatal – is so rare that it can simply be discounted. Taking myself as an example; I am aged 55 and in good physical condition with no existing health conditions. I am not overweight. The chances of my dying from Covid-19 are remote. It is therefore a rational decision for me not to get a vaccine in the UK – in particular since I cannot specify that I don’t receive AstraZeneca. (In the UK only people under 40 are being automatically offered Pfizer or Moderna). The information offered by the NHS that “the benefits of being vaccinated with the Oxford/AstraZeneca vaccine outweigh any risk of clotting problems” is probably not true in my case. It is simply misinformation. (“blood-clotting problems” is further misinformation since the fact is that 17%-20% of these will be fatal; not just a ‘problem’). At any event surely it is up to the patient to make the risk-decision assessment herself? Isn’t there some principle of “informed consent” which has simply been abandoned here?
Another lie told by the NHS is this one: “The COVID-19 vaccine can help stop you getting seriously ill or dying from COVID-19.” This pretends there is a single vaccine. In fact there are multiple vaccines which use a range of different technologies and which carry different risk profiles. Again; surely it is the job of the NHS to present accurate information about treatments and allow patients to make their own choices? AstraZeneca has a risk of blood-clotting. Pfizer carries a risk of heart inflammation – especially in younger men.  These risks appear to be of a very small percentage and rarely fatal; less serious than the AstraZeneca blood-clotting problem.
We are supposed to live in free democratic and scientifically literate society. This is why millions of young people who are destined to become builders and hospital porters and florists are nonetheless forced each year to take exams in biology and chemistry and physics. So they can participate in a modern rational and scientifically aware society. But instead of offering actual information which enables people to make up their own minds the health bureaucracy feeds them untruths and tries to make up their minds for them. It is mind-bogglingly irresponsible.
Meanwhile the police are investigating a woman who made a speech at a public event in London in which she apparently compared doctors and nurses promoting vaccination to Nazi war criminals and referred to the Nuremberg trials.  This is obviously going too far and is extremely idiotic. But amidst the idiotic analogy she may have a point; there is a push to vaccinate and a sustained effort to supress information about the risks. Most outlets are not even reporting the rest of her speech. The BBC is rare in saying that “Speaking about the vaccine, she encouraged the crowd to challenge vaccinators about its safety.” So – the NHS can publish what is manifestly false information about the risks from the vaccines but someone who calls for this narrative to be questioned is subject to police investigation. This really is rather Orwellian.
The state health bureaucrats wonder why there are so many conspiracy theories. Such as RNA vaccines will alter your DNA. But one reason is that people can tell when they are being lied to. This is what creates the ground in which conspiracy theories flourish. The public health bureaucracy has decided on a campaign of mass vaccination and they are not going to let scientific fact or the principle of informed consent get in their way. The conspiracy theories are the inevitable blow-back.