The vaccines have only been tested over the short term, the long term issues are quite unknown. The official testing of these vaccines will be complete in 2023, until then they are classed as ‘Experimental’…
https://www.nature.com/articles/d41586-020-03441-8
Quote:
[I]The approval is a historic moment. But scientists still have many questions about how this and other vaccines will perform as they’re rolled out to millions of people.
Do the vaccines prevent transmission of SARS-CoV-2?
In addition to the Pfizer vaccine, regulators are poring over data from a similar vaccine made by Moderna of Cambridge, Massachusetts, and a third produced by AstraZeneca of Cambridge, UK, and the University of Oxford, UK. All three have been tested in large clinical trials, and have shown promise in preventing disease symptoms.
But none has demonstrated that it prevents infection altogether, or reduces the spread of the virus in a population. This leaves open the chance that those who are vaccinated could remain susceptible to asymptomatic infection — and could transmit that infection to others who remain vulnerable. “In the worst-case scenario, you have people walking around feeling fine, but shedding virus everywhere,” says virologist Stephen Griffin at the University of Leeds, UK.
The major vaccine trials so far have enrolled tens of thousands of people, but for each one, conclusions about effectiveness are drawn from fewer than 200 people who have developed disease. As a result, it can be difficult to break up the data to look at efficacy in different groups — such as people who are obese or elderly — without losing statistical power. “We need to see more data in terms of effects of vaccines across different demographics,” says Michael Head, an infectious-disease researcher at the University of Southampton, UK.
There are early indications that the three leading vaccines protect people over 65. But researchers will probably need real-world data from large numbers of vaccinated people before they can get the demographic granularity necessary to ensure that parts of the population aren’t left unprotected.
How will scientists monitor for long-term safety concerns?
“The public’s safety has always been at the forefront of our minds,” said June Raine, chief executive of the UK Medicines and Healthcare products Regulatory Agency (MHRA), in a statement that accompanied the UK announcement that it had approved the Pfizer vaccine.
The vaccine has completed only a few months of the two-year clinical-trial period that it will need to complete before it is approved to be sold freely on the market. As a result, health officials, clinicians and people receiving the vaccine will be watching closely for as-yet unobserved signs of danger.[/I]
