Tomorrow the first shipment of vaccines from the laboratories will arrive in Spain Janssen/Johnson&Johnson. This Wednesday some 300,000 doses of the 5.5 million that will enter the country between April and June. It will be the fourth vaccine that is used and one of the six that Brussels has acquired in the centralized purchase for the European Union. The first doses will arrive, for the moment, for a very specific population group, that of 70 to 79 years of age. They are now the objective of the Ministry of Health for being the most vulnerable, once that of the oldest and the essential groups or those with greater risk due to their profession has been completed.
In addition, the drug will begin by injecting those older than 70 years who have not had the infection recently. With those who already have antibodies, they will wait six months, the time of natural immunity that conferring having overcome the Covid-19. In a time of scarcity, too preference will be given to those who do not yet have any type of protection against the virus. This serum does not have any age restrictions and is indicated for those over 18 years of age.
Janssen’s is the most special vaccine licensed to date. Not so much because of its technology, which is reminiscent of AstraZeneca’s, but because a single dose is enough to achieve sufficient protection and avoid the hospital and life-threatening complications.
Any vaccine provides good protection from the first dose, but not as complete as Janssen’s. The overall protection is more than 66%. It may seem meager when compared to 90% of the two doses of Pfizer or Moderna. “That does not mean that Janssen is a worse vaccine than the previous ones. It has been shown in clinical trials to be highly effective against the virus and its variants and 100% avoidance of hospitalization and death. It is a terribly practical vaccine. It will make it possible to protect the population that is now the most vulnerable and act in an emergency situation ”, points out José Ramón Arribas, head of Infectious Diseases at Hospital La Paz in Madrid.
In this health center they know well the medicine of the Belgian pharmaceutical company. This hospital is one of those participating in the clinical trial that evaluates its efficacy, the only trial conducted in our country with vaccines.
Curiously, in Spain the results of this single-dose vaccine with two injections are being evaluated. Three thousand Spanish volunteers test whether a double dose is even more effective in global protection and if it is capable of providing a longer lasting immunity. There are no results yet on this possibility.
Four cases of thrombi
The technology on which this drug is based is similar to that of traditional vaccines. To activate the immune system, it uses a human viral vector, adenovirus 26. This infectious agent causes colds but has been modified to be harmless. and activate defenses with SARS-CoV-2. The AstraZeneca or the Russian Sputnik V follow a similar strategy, although they use different viral vectors. The first uses a chimpanzee adenovirus and the Russian two different viral vectors.
In the United States, where 10.6 million people have already been inoculated since March 1, adverse reactions have been rare. The most common were mild: pain in the area of the puncture, headache, fatigue, muscle pain, fever and intestinal discomfort. But last Friday, the European Medicines Agency announced that it was investigating the appearance of four cases of thrombosis after the injection. One of them was detected among participants in clinical trials and another three in the United States, where it is already part of the general population vaccination campaign. There are only four cases of more than ten million punctures, an even greater rarity than that detected with AstraZeneca.