THL: Late autumn coronavirus booster not currently recommended for health and social services professionals
The Finnish Institute for Health and Welfare (THL) does not currently recommend the coronavirus booster vaccine available in late autumn for health and social services professionals who have no chronic illnesses. The risk of contracting a severe coronavirus disease caused by the currently circulating Omicron variants is very low for previously vaccinated adults at working age with no chronic illnesses.
Not enough research evidence is available to support the administration of booster doses to health and social services professionals at the moment.
"Vaccines tailored to specific variants are recommended as booster doses to broaden the range of the immunological response. However, we do not yet know what level of protection they afford against infections compared to the original vaccine products, and what impact this might have on sickness absences", says Merit Melin, Research Manager at THL.
At best, protecting health and social services professionals against infections and infectiousness could also indirectly protect patients and residents at institutions providing long-term care. However, the protection provided by the original coronavirus vaccine products against infections is only moderate and short-term, or a few months.
Many people already have hybrid immunity
THL studies have found that a large proportion of the population have antibodies indicating a coronavirus infection. The proportion of those who have contracted the infection increased in spring and summer 2022.
THL examined the presence of antibodies in serum samples taken from children aged 1 to 17 at HUSLAB for reasons other than laboratory tests associated with COVID-19. Antibodies indicating a coronavirus infection were found in 73% of the samples taken in May.
The proportion of adults who have contracted the infection was assessed in a population study based on a random sample. In March, antibodies indicating a coronavirus infection were found in 27% of samples from persons aged 18 to 84 who participated in the study in the hospital district of Helsinki and Uusimaa (HUS). In May–June, 35% of those who participated in the study in HUS hospital district and four other hospital districts had these antibodies. In younger age groups, a larger proportion of subjects had antibodies indicating an infection.
Antibodies were found in different age groups in May–June as follows:
- Aged 18 to 29: 55% (n=66)
- Aged 30 to 44: 46% (n=196)
- Aged 45 to 64: 36% (n=519)
- Aged 65 to 85: 28% (n=464)
“As the proportion of infected persons grew to a significant level during the Omicron wave of spring 2022, especially in the youngest age groups, a very large share of those aged 12 or over have hybrid immunity formed as the combined effect of a coronavirus infection and vaccinations. Hybrid immunity is stronger and recognises a wider range of different virus variants compared to protection developed as a result of an infection or vaccination alone”, Melin explains.
Research evidence of variant-tailored products’ improved efficacy not yet available
Some European countries recommend booster doses for health and social services professionals this autumn.
"No research evidence showing that variant-tailored products are more effective than reference products is available to support the decisions. The recommendations are based on a hope that variant-tailored products would be more effective in preventing infections", says Hanna Nohynek, Chief Physician at THL.
"THL issues its recommendations on booster vaccinations on medical grounds", Nohynek emphasises.
If a health and social services professional belongs to the target group for booster doses in autumn 2022 due to their age or a chronic illness, a booster vaccine is recommended for them in the same way as for others in the same target group.
Get the winter booster dose in November or December
The Finnish Institute for Health and Welfare recommends another coronavirus booster dose in late autumn for all those aged 65 or over, those aged 18 or over who are in medical at-risk groups, and those aged 12 or over with severe immunodeficiency. You can take the booster vaccine when at least three months have passed since you had your previous vaccination or contracted the disease.
"Your previously formed immunity also affects the additional protection you obtain from the vaccination. If you had the previous vaccination or the illness a short period ago, such as a few months, you still have a good level of previously formed immunity. In this case, the response and additional protection against infections you gain from the booster dose may be minor", says Melin.
It is advisable to take the booster dose together with the influenza vaccine. Influenza vaccinations are usually administered in November–December. You should get the booster vaccine by the end of 2022.
In booster vaccinations, variant-tailored products are mainly used. THL does not rank any of the different variant-tailored products as better than others. All of them broaden the range of immunological response triggered by the vaccinations and effectively prevent serious coronavirus disease.
The research conducted so far has found that somewhat higher levels of neutralising antibodies against Omicron have been achieved with vaccine products tailored for this variant compared to the original vaccine product in subjects who had previously received three doses of the original product. However, the amount of antibodies neutralising Omicron remained low compared to antibodies neutralising the original virus.
THL's previous recommendations on the basic series and boosters of coronavirus vaccines are still valid. The recommendations on coronavirus vaccines are based on joint assessments of the National Advisory Committee on Vaccines and the Finnish Institute for Health and Welfare.
Municipalities organise vaccinations and will specify where and when COVID-19 vaccines can be obtained.
THL is monitoring the coronavirus situation and, if necessary, will adjust its vaccination recommendations on medical grounds.
Further information:
Merit Melin
Research Manager
THL
[email protected]
Hanna Nohynek
Chief Physician
THL
[email protected]
