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Never before has any vaccine been developed as rapidly and efficiently as the vaccines for COVID-19 that are now on the market. The rapid pace is partly due to the fact that the genetic code for the SARSCoV-2 virus was made public, enabling researchers across the globe to study it. – But the research on which the vaccine is based has actually been around for a long time, and was initially developed to produce preparations for HIV, Ali Harandi explains.

Text: Eva Lundgren Photo: Johan Wingborg Illustration: Maria Källström De vacciner som PfThe vaccines developed by Pfizer-BioNTech and Moderna are so-called mRNA vaccines, explains Ali Harandi, Associate Professor of Clinical Immunology, and head of the vaccine laboratory at the Institute of Biomedicine. – They primarily consist of mRNA, the very blueprint for the SARS-CoV-2 virus’s spike protein. In order for the mRNA to enter a muscle cell at the injection site, it is encased in a small lipid particle. The mRNA subsequently instructs the cells to produce the coronavirus’s spike protein. The immune system thinks it is a foreign intruder and starts to protect the body by producing antibodies and perhaps cell-mediated immunity.

The vaccine produced by AstraZeneca, on the other hand, is a vector-based vaccine. – That means that the vaccine uses a weakened common cold virus that has been manipulated into producing the coronavirus protein. When the virus, disguised as the coronavirus, turns up in the body, the immune system recognizes it as an intruder and defends the body against it. Unlike the mRNA vaccine, there have been vector vaccines for human use for some time; a very successful one is the Ebola vaccine that was developed two years ago.

Another vector vaccine, manufactured by Johnsson Ï

The lesson humanity needs to learn, is the importance of safeguarding nature. Because most pandemics are caused by the transfer of a virus from animals to humans.

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& Johnsson, has been considered safe and effective, and has recently got emergency use approval from FDA, the US Food and Drug Administration.

The vaccines that are currently available are based on research that has been going on for many years. Several million dollars have been invested in research since 1984, in an attempt to find a vaccine against HIV, says Ali Harandi.

– Despite the herculean efforts, no HIV vaccine has yet been produced. But the research has been successful nevertheless, as we have learned much about the workings of the immune system and about how to induce immunity against viral infections. The fight against HIV has also resulted in several new technical methods being developed, such as for producing both nucleic acid vaccines and vector-based vaccines.

The COVID-19 vaccines are administered in two doses, the first one to wake up the immune system, and the second one to boost the immune system, Ali Harandi explains. – You probably receive partial protection even after the first dose. But it will take up to two weeks following the second dose for the body to build up effective protection against the disease. We do not actually know how long that protection will last, though.

However, the forth vaccine, manufactured by Johnsson & Johnsson, is only given in one dose. Clinical data shows, though, that these vaccines have less efficacy compared to the mRNA vaccines.

None of the new vaccines seem to cause serious adverse effects. – The adverse effects that have been observed are

■ Facts

How does the COVID-19 vaccine work?

mRNA vaccines are an entirely new way of making vaccines which involve activating the body’s own cells at the injection site. What happens is that a sequence of the virus’s genetic make-up, or RNA, is injected into the body’s cells. The RNA acts as a template for the spike protein, the protein on the surface of the virus that acts as a kind of key, enabling the virus to penetrate human cells. The antibodies bind to this key and deactivate the virus. The vaccines from Pfizer-BioNTech and Moderna are mRNA vaccines. Astra-Zeneca’s vaccine, on the other hand, is a vector-based vaccine. It involves loading a weakened common-cold virus with the genetic material for the spike protein of the coronavirus. The cells then start to produce antigens that the immune system learns to recognise. As the vaccine does not contain any complete coronavirus, it cannot cause any illness. Astra-Zeneca’s vaccine is considerably cheaper than the other two vaccines, and is also easier to handle from a logistical perspective. However, there is some uncertainty as to its efficacy in older people. Another vector vaccine, manufactured by Johnson & Johnson has recently been considered safe and effective, and has been given emergency use approval from FDA.

the ones that usually arise following an influenza vaccination, such as localised pain at the injection site, fever and fatigue. However, COVID vaccines appear to be reactogenic more often compared to other human vaccines, so adverse reactions are more common.

It might also be good to combine different vaccines. A study was recently commenced at Oxford University, where over 800 people will first be given a dose of the AstraZeneca vaccine, and then a dose of the Pfizer vaccine. – It is a very interesting study, Ali Harandi points out. If it is possible to combine the vaccines, worldwide distribution will be more flexible with less risk of delays. A combination may also provide greater efficacy as the immune system is being attacked from different directions, but we do not yet know whether that holds true in this case. Like many other types of virus, the SARS-CoV-2 virus has mutated and there is currently a British and a South-African variant. These mutations appear to spread more rapidly in the population than the original variant, but the symptoms are the same. There is also a Brazilian variant which so far has not spread very extensively. – The new vaccines provide somewhat weaker immunity against these mutated viruses, particularly against the South-African variant. But the next generation of COVID vaccines, which also work against the mutated viruses, are already being developed. But the fact that the virus mutates is yet another reason to ensure that as many people as possible are vaccinated, to stop the contagion. Because when it comes to pandemics, nobody is safe until everybody is safe.

The approvals that have now been granted for a number of COVID vaccines are conditional. This means that they may only be used during a public health emergency, such as a pandemic, says Ali Harandi.

– For the general public, this is less relevant but to the pharmaceutical companies, it means that they will have to submit additional information in order to subsequently apply for full approval.

Ali Harandi believes that life will only return to something resembling normal in 2022. Moreover, he is convinced that the world will suffer more pandemics in the future. – The lesson humanity needs to learn, is the importance of safeguarding nature. Because most pandemics are caused by the transfer of a virus from animals to humans. This in turn, is due to man’s destruction of natural animal habitats, such as deforestation, which leads to viruses crossing the natural species barrier. Being able to buy live bats and other wild animals at markets in China, and cramming animals, such as mink, together on massive farms in countries such as Denmark, increases the risk of a contagion spreading. Humans are simply close at hand when the virus is looking for a new host. Previous epidemics, such as SARS, MERS, Ebola, Zika, influenza and HIV were all transmitted from animals. So, if we want to prevent future epidemics, which may well be much more serious than COVID-19, we must start treating animals and the environment in a much more responsible manner.

Because when it comes to pandemics, nobody is safe until everybody is safe.

ALI HARANDI