Will delaying the second Covid-19 vaccine jab work?

British health officials are delaying the administration of the second Covid-19 jab in order to provide more people with some protection from a single jab, but there is no evidence this will work as hoped. — dpa

In an effort to faster provide a basic level of Covid-19 immunity to a larger section of the population, health officials in the United Kingdom have decided to delay the second of the two vaccinations needed for long-term protection.

In theory, this means more people will get a fundamental level of immunity from a first vaccination, but also that people have to wait longer for their second vaccination.

However, health officials in the European Union and the United States are sceptical about allowing people to wait any longer than is needed before getting a second vaccination, and are advising those being immunised to stay within the recommended interval – currently set at a maximum of six weeks.

“The administration of the second vaccine dose should take place within the period covered by the licensing studies (currently 42 days),” the Robert Koch Institute (RKI), the body handling disease control in Germany, says.

The European Medicines Agency has already pointed out that any change in the timing of the two vaccine doses would mean a change to its legal authorisation, and also require more clinical data.

The US Food and Drug Administration (FDA) meanwhile has also warned against deviating from the prescribed administration of the two doses.

A change to the time frame should only be considered if there is scientifically-sound data proving the interval could be extended, the agency says.

The reason for the concern, according to the RKI and other officials, is that it’s currently uncertain whether postponing the second vaccine to a later date can, in practice, prevent more severe illnesses and deaths, as British health officials hope.

British authorities are planning to extend the interval between vaccinations to 12 weeks – twice the current recommendation.

Instead, German health officials say the only way to ensure complete protection against the disease, especially for high-risk individuals, is with a prompt second vaccination.

Vaccine manufacturer BioNTech had pointed out that in its phase 3 clinical trial, the safety and efficacy of the vaccine were only examined with an interval of 21 days between vaccinations.

If the recommended interval between the first and second vaccine doses is exceeded, doctors in Germany are, however, unlikely to restart the vaccination procedure and will still continue with a second jab.

For those getting the vaccine, this means it’s essential to stick to the schedule given to you by your healthcare officials. – dpa