Netherlands approves Novavax Covid vaccine; Won't use Janssen boosters

The Netherlands has approved the use of the protein-based Covid-19 vaccine, Nuvaxovid, from pharmaceutical firm Novavax. Caretaker Health Minister Hugo de Jonge informed the Tweede Kamer that he expects the first delivery of doses to happen no sooner than the end of February or early March.

It will be possible for people to opt for Nuvaxovid if they have health concerns related to the other vaccines in use in the Netherlands. De Jonge will continue to advise unvaccinated people to use an mRNA vaccine, such as Pfizer or Moderna, for their first injection series. He is therefore following the advice issued by the Dutch Health Council. Although mRNA has been tested since 2011, some people object to using it because the technology is newer. Nuvaxovid is based on an older vaccine production techniques.

The Novavax vaccine requires two shots, separated by three weeks. The vaccine contains a counterfeit "spike protein" meant to emulate the coronavirus. This protrusion triggers an immune system response.

The effectiveness of Nuvaxovid is between 60 and 90 percent, De Jonge wrote. According to the Health Council, this is comparable to the mRNA vaccines when they were allowed on the market. It is plausible that Nuvaxovid, like the mRNA vaccines, provides less protection against the Delta and Omicron variants. Earlier this week, Novavax wrote positively about its early research into their vaccine's effectiveness against Omicron.

The Novavax vaccine has only been evaluated for use in the Netherlands as a first and second vaccination, and not yet as a booster shot. It is also not yet known whether there are any very rare side effects, because the vaccine has not yet been widely used like the other vaccines which entered the market over the last 12 months.

No Janssen vaccine boosters

The Health Council also advised the Ministry of Health not to use the Janssen Covid-19 vaccine as a booster shot "for the time being." It wrote on Friday that booster shots with the Pfizer and Moderna vaccines seem to work better, especially for people who were previously vaccinated with the one-shot Janssen vaccine.

De Jonge also implemented this advice Friday evening. "For the booster campaign, I will stick to the primary use of an mRNA vaccine as protection against COVID-19," he wrote to the Tweede Kamer.

"Boosting with the Janssen vaccine initially seems to lead to a lower increase in antibodies than boosting with an mRNA vaccine," the Council said. "It is still unclear what the effect of the booster will be on the level of the antibodies after a few months."

The Council said that the booster is safe, but also noted that the Janssen vaccine carries a risk of a rare but serious side effect, where a patient develops thrombosis in combination with a reduced number of platelets. This is more common in younger people. It is not yet known how great the risk of this side effect is after a booster shot with Janssen. The European Medicines Agency (EMA) already ruled that Janssen's vaccine can be used as a booster, prompting the ministry to request the Council's advice.

There may be other reasons for using Janssen as a booster vaccine, the Council concluded. For example, it presents advantages regarding transport or storage options. And there may also be people who do not want a booster shot with an mRNA vaccine. "The choice to offer Janssen's vaccine as a booster in such cases must be weighed against the uncertainty surrounding the degree of protection it offers."

The ministry still plans to offer the Janssen vaccine to people who have specific health reasons that preclude them from using the Pfizer or Moderna vaccine for their initial vaccination.