Dutch hospitals studying booster shots for Janssen Covid-19 Vaccine recipients

Four academic hospitals in the Netherlands will investigate if it can be useful to administer a booster shot to people who received the Janssen Vaccine from Johnson & Johnson. The aim of the study is to find out if the jab is more effective on its own as a single shot, when administered in two doses, or when used in combination with the vaccines from other producers.

"Due to the increasing circulation of certain variants of the coronavirus, it is possible that an additional vaccination is necessary after one shot from Janssen," stated the Erasmus Medical Center. As of right now, the vaccine developed in Leiden is considered to offer its full level of protection against Covid-19 after a single shot.

In addition to Erasmus MC, Amsterdam UMC, Leiden UMC, and UMC Groningen will also participate in the research. A number of employees from the four hospitals will take part in the study. Part of them will be given the Jannsen Vaccine as their booster shot, while others will receive vaccines from Pfizer/BioNTech or Moderna.

The first results of the study are expected in October. “The researchers are mainly studying whether the combinations are safe and whether this elicits a good immune response. They will also study the immune response against the different coronavirus variants, because combining vaccines could lead to a broader immune response,” Erasmus MC stated.

Numerous studies into combining Covid-19 jabs are currently underway in many countries. ”By mixing vaccines, vaccination campaigns become more flexible, the vaccination process can be accelerated and the impact of delivery problems can be reduced,” Said Dr. Hugo van der Kuy, the Head of Pharmacy at Erasmus MC.

Caretaker Health Minister Hugo de Jonge has approached the Dutch Health Council in May to find out whether different Covid-19 vaccines can be safely combined. The advice from the advisory body on the matter was expected at the end of May.

The Health Council said they were still working on advice but could not precise when it would be released. They explained they still had too little information about it and were awaiting the outcome of several studies, including a large one in the UK.