THL issues guidelines for intervals between COVID-19 vaccinations and the use of vaccines for different age groups

The Finnish Institute for Health and Welfare (THL) has issued its guidelines for the use of different coronavirus vaccines. The policies apply to the targeting of mRNA and adenovirus vector vaccines to different age groups, and the intervals between the first and second doses of the vaccines.

Those over the age of 65 may be given two different vaccine preparations in exceptional cases

Those aged 65 years and over will now be able to take an mRNA vaccine even if the vaccination series began with the AstraZeneca adenovirus vector vaccine.

“Our recommendation remains that those aged 65 and over should continue their vaccination series with the coronavirus vaccine they had received earlier if no medical impediment has emerged for its use. However, a person who was given the AstraZeneca vaccine and refuses to take a second dose of AstraZeneca, may be given an mRNA vaccine now as those who are in a high-risk group have mostly been vaccinated and as mRNA vaccines are now more easily available”, says Emma Kajander, Specialist Physician at THL.

“Taking a second dose of the vaccine is very important for ensuring that the protection afforded by the vaccine would be as strong and enduring as possible.”

Nearly 365,000 people in Finland have received the AstraZeneca vaccine. A very rare blood coagulation disorder has been linked with the adenovirus vaccines which has been detected mainly among persons under the age of 65.

Only mRNA vaccines for those under the age of 65

Already now everyone has the option to start their series of vaccines with the mRNA vaccine - either the Moderna or Biontech-Pfizer vaccine. 

Those under the age of 65 will be given only the mRNA vaccines – the  Moderna and Biotech-Pfizer vaccines. The mRNA vaccines are administered also to those under 65 who were given the AstraZeneca vaccine as their first dose.

“We are expecting research results in early June on administering different vaccines to the same person. We know that the use of different coronavirus vaccines back-to-back can cause more side-effects such as fever, muscle pains, and fatigue, which last a few days. However, available research results, experience, and prior immunological knowledge do not give cause for concern about the overall safety or effectiveness of the vaccines. Therefore, it is possible to give different vaccine preparations to the same recipient already now”, says THL Chief Physician Hanna Nohynek.

Persons under 65 may not get an adenovirus vector vaccine even if they want the AstraZeneca vaccine.

“The reason for this is that in today's epidemic situation there is no medical justification for giving an adenovirus vector vaccine to those under the age of 65. With them, the very small risk of blood coagulation linked with the AstraZeneca and Johnson & Johnson vaccines is greater than among those who are older”, Nohynek says.

Vaccines in Finland must be used according to medical indications and established treatment practices so that all who are vaccinated are under insurance cover.

Flexibility in intervals between vaccines – vaccinations should take place in a person's own home municipality

The interval for mRNA vaccines remains at 12 weeks. The interval may be shortened only for medical reasons, such as the start of cancer treatment, or for well-founded personal reasons. A long interval between doses reinforces the protective effect of the vaccine and provides the protection given by the first vaccination to as many people as possible. 

The interval for the AstraZeneca vaccine will be 8-12 weeks. The interval can be shortened from 12 weeks, because it will not slow the progression of coronavirus vaccinations. Shortening the interval between doses of the mRNA vaccines will be reconsidered once all of those over the age of 16 have been given their first doses of the vaccine.

THL recommends that everyone should take their first and second doses of the vaccine in their own home municipalities. If it is not possible to take a vaccine at the right time in one's own home municipality, the time of the vaccination can be changed, and the length of the interval between doses can be extended beyond 12 weeks. 

“Getting a vaccine outside of one's own home municipality is possible only in the exceptional case in which a person’s stay in the other municipality takes place over a long period of time, getting a vaccination from the person’s own municipality is very difficult, and the vaccination can be provided by the other municipality. Vaccines are distributed to the different municipalities based on the home municipalities of the people, which is why it is not possible for municipalities with many holiday homes to vaccinate many residents of other municipalities”, Kajander observes.

Johnson & Johnson vaccine not used in Finland for now

The Johnson & Johnson coronavirus vaccine, which has been given a sales licence in the EU, is an adenovirus vector vaccine like AstraZeneca. It is not being included in the Finnish vaccine programme for now.

“There is no need for the Johnson & Johnson vaccine in the current epidemic situation in Finland, because it would be given only to those aged 65 and older, just like the AstraZeneca vaccine. Most of the people in this age group have already been vaccinated. However, the selection of vaccines will be re-examined if Finland’s epidemic situation begins to deteriorate”, Nohynek observes.

Further information:

Emma Kajander
THL
Specialist Physician
[email protected]

Hanna Nohynek
Finnish Institute for Health and Welfare
THL
Chief Physician
[email protected]