Spain to offer Pfizer or Moderna booster shot to recipients of single-dose Janssen vaccine

Spain’s Public Health Commission, which is made up of the Health Ministry and the country’s regions, approved on Tuesday the administration of a booster shot of either the Pfizer-BioNTech or Moderna Covid-19 vaccine for the nearly two million citizens who initially were given the single-dose Janssen medication. The decision has been taken after a recent study revealed that people who were given the latter vaccine had lower protection from the coronavirus than those who had been given the others, which are known as mRNA vaccines. The new shot will be administered at least three months after the first.

The Health Ministry announced on Tuesday that “the autonomous regions will begin with this booster shot from November 15, prioritizing vaccination groups from the National Vaccination Strategy.” This means that first in line will be older people or those who are members of other risk groups. The decision was taken after a proposal was made by the board of experts who are advising the Health Ministry on the overall strategy that it should follow.

For José Luis Barranco, the spokesperson of the Spanish Society of Preventive Medicine, Public Health and Hygiene (SEMPSPH), the decision is due to the fact that “while the Janssen vaccine has shown to be effective, it is somewhat less so than the others that are available.” He continued, saying that “in a scenario of availability of mRNA vaccines, and after confirmation that a heterologous approach [i.e. administering a different dose after the first] is safe, this measure is recommendable.”

Vaccines have been a key tool for bringing the coronavirus pandemic under control in Spain. According to the latest data from the Health Ministry, released on Tuesday evening, 90.2% of the target population (i.e. those aged over 12) have received one dose of a Covid-19 vaccine, while 88.4% have the full protection offered by the medications. For the entire population, these percentages are 88.4% and 78.5%, respectively. The under-12s are the only group so far not to have been included in the vaccination campaign, although that could soon change if authorization is granted by the health authorities.

The ministry also reported last night that Spain has now registered more than five million official coronavirus infections, while the death toll stands at 87,238. A further 1,926 new cases and 52 Covid-related victims were added to these totals on Tuesday. The 14-day cumulative incidence per 100,000 inhabitants dropped slightly, according to the report, by 0.37 points to 46.01. The incidence rate has been below 50 – considered the barrier for low risk – since early October, and has been rising and falling slightly since then.

A recent report from the Health Ministry, which was dated October 13, revealed that all of the vaccines used in Spain – the aforementioned three, plus Oxford-AstraZeneca – have contributed to this situation, albeit with some differences in the protection levels offered by each one, according to the data analyzed so far.

These results, however, always have an element of uncertainty, given that the same vaccines have not been administered in the same proportions to all population groups, meaning that some variations may be due to the vaccine itself, and some to the characteristics of the population that has received it – i.e. age, pre-existing conditions – or indeed a combination of both these factors.

Despite this, the differences found are significant and justify the decision adopted by the Public Health Commission, according to sources consulted by EL PAÍS. The variables analyzed are cases of infection with mild symptoms, hospitalizations and deaths. In all of them, the Janssen vaccine shows lower effectiveness than the mRNA vaccines: Pfizer and Moderna. The percentage for protection against deaths, for example, is 89% for Janssen compared to 97% for Pfizer and 94% for Moderna.

In the case of hospitalizations, the study concludes that the effectiveness of Janssen is 86% compared to 98% for Moderna and 97% for Pfizer. An in the case of infections with symptoms, albeit mild, where the data for the single-dose vaccine is worse, the report shows an effectiveness of 56% compared to 89% for Moderna and 78% for Pfizer.

The data support that all of those people who received the Janssen vaccine should now get an mRNA booster shot

Santiago Moreno, the head of the infectious diseases service at the Ramón y Cajal Hospital in Madrid

The study also detected the effectiveness of the heterologous approach in Spain for people who were given a first dose of AstraZeneca (a vaccine that works in a similar way as the Janssen) and the second of Pfizer, with protection levels that are very similar as for those who were given two doses of an mRNA pharmaceutical.

Santiago Moreno, the head of the infectious diseases service at the Ramón y Cajal Hospital in Madrid, said that this data “support that all of those people who received the Janssen vaccine to now get an mRNA booster shot.” As for the heterologous approach, Moreno added that patients would benefit from this second shot given the “increase in antibodies to combat the virus that will be caused by this dose,” and that the new measure “is sensible given the detection of a greater rate of breakthrough infections, in particular cases of symptomatic infections.”

Even before this data arrived, healthcare services had already detected some episodes that suggested a lower effectiveness of the Janssen vaccine. Being single-dose, the medication was primarily aimed at collectives where administering two doses in the established time frame would be more difficult – whether due to their professional activities or personal situation. It was also given to a small proportion of the 70-79 age group.

One of these collectives was those who work at sea, in particular fishermen who spend long periods of time on ships. In these cases, there have been frequent outbreaks in recent months. The data from the Health Ministry has supported the suspicions that the Janssen vaccine was not as effective as others.