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Medicine And Health

The suspension of the Janssen vaccine complicates the goal of group immunity

Harry Watson

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In January there were suspensions of the first doses and shortages to inoculate the second due to production problems at Pfizer and Moderna’s delays in the delivery of vials. In March, the cases of blood clots in those vaccinated with AstraZeneca that severely eroded confidence in this vaccine and forced a reconsideration of the age groups it was aimed at. And in April, new cases of thrombi in young and middle-aged women vaccinated with Janssen in the United States , something that led to Johnson & Johnson paralyzing the administration of doses of its own vaccine.

The vaccination race against COVID-19, one of the great events of our lives, is presenting some complications, and the latter is especially delicate: Janssen’s is a key vaccine to reach the deadlines set by the Government of Spain , which set for the last week of August the figure of 33 million vaccinated: 70% of the Spanish population, and therefore, the longed-for group immunity. However, the vaccine that does not need deep freezers or a second dose is on a pause from which it will be necessary to see when it comes out, and in what form . Any day that passes without recourse to its doses will further jeopardize the achievement of the summer goal.

The first group to be administered this vaccine before the pharmaceutical company announced a suspension of its administration was citizens between 70 and 79 years old, who until now had also received doses of Pfizer and Moderna.

A day before the first single doses of Janssen were to be administered in Spain, this Wednesday, April 14, the recommendation of the Center for Biological Evaluation and Research of the United States Food and Drug Administration appeared, who asked to stop administering doses of this vaccine after detecting six cases of thrombi in women between 18 and 48 years old who had received it. One such case was fatal, and a total of 6.8 million Americans received the Janssen dose. An event similar to the one that occurred weeks ago with AstraZeneca and that resulted in only those over 60 years of age receiving this vaccine , although its benefits continue to outweigh its risks .

Time to do the math and launch hypotheses regarding Janssen to see what Spain needs to reach the goal set, that of group immunity at the end of August. As of April 13, according to the Ministry of Health:

Administered dose : 11,073,567.
Vaccinated with the complete schedule : 3,136,091.
Vaccinated with one dose : 7,937,566.
Days until August 31 : 139.
Average daily dose in the last week : 298,379.
Janssen Spain 001
The Government’s forecasts regarding the doses received in the coming months reach the month of June, the second full quarter. By then, 20 million doses from Pfizer, 7 million from AstraZeneca, 5.5 million from Janssen (equivalent to 11 million from the rest of vaccines) and 3.5 million from Moderna are expected to arrive.

To achieve group immunity (33 million vaccinated) in Spain in the last week of August, it would be necessary to continue putting doses until reaching 66 million by then. If there are already more than 11 million administered, and all the vaccines used so far are double doses, the figure that remains between now and August 31 is exactly 54,926,343 doses . In the 139 days until that date, there is an average of 395,154 daily doses needed, counting that they are all double. Let’s see what happens in two different scenarios regarding the use of Janssen, which would lower that figure.