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Vaccines for COVID-19: vector vaccines


Vector vaccines are produced using a relatively new technology which, among other things,  involves genetic techniques. After the genome of a new virus has been sequenced, this technology enables the rapid production of an effective vaccine. In view of the current pandemic, two vector vaccines have meanwhile been given a conditional marketing authorisation by the EMA, the AstraZeneca COVID-19 vaccine (new brand name Vaxzevria®), and the COVID-19 vaccine by Janssen (Johnson & Johnson). Several other vector vaccines have been produced, such as the Russian and Chinese vaccines, but these have not yet been authorised by the EMA. 

  • The relatively short time required to develop and produce a vector vaccine, for instance after a mutation has emerged, is an advantage in an outbreak and a pandemic. 
  • Clinical research has shown that vector vaccines effectively reduce the number of COVID-19 infections. The adverse effects appear to be mild. 
  • Advantages of vector vaccines include their ease of use, their storage temperature (refrigerator) and the single dose required for some of the vector vaccines.
  • Many questions remain wholly or partly unanswered, such as whether the efficacy of the various vaccines is comparable, their efficacy in the population of older adults, their adverse effects in the longer term, contagiousness after vaccine administration, the duration of the protective effect, the efficacy after administering a single dose, whether the vaccines are interchangeable, and whether they can be applied for specific target groups and for mutated forms of the virus.
This article refers as much as possible to the current situation regarding the use of vector vaccines for COVID-19 and has been updated until just before publication. Studies and reports published after 7 April 2021 could not, however, be reviewed here.

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Authors

  • Leo M.L. Stolk, dr