Two doses of the coronavirus vaccine provide good protection against serious disease caused by omicron, 3rd dose gives excellent protection

Two doses of any coronavirus vaccine used in Finland already provide good protection against serious disease requiring hospitalisation due to the omicron variant. A third dose of vaccine further improves the level of protection. 

In a UK study, the protection of coronavirus vaccines against serious disease was found to be good, 72% even 5 to 6 months after the second dose but dropping to 52% after six months. After the third dose, the protection improved to a nearly excellent level of 88%. 

Further research data is needed on whether protection against serious coronavirus disease differs for risk groups and older people. We also need a better understanding of the protection offered by different vaccine preparations. 

Less protection against mild disease 

It seems that the protection provided by coronavirus vaccines against mild coronavirus disease caused by omicron is clearly reduced. After 3 to 4 months, the protection provided by the second dose of vaccine is low, 0–20%. The level of protection from the third dose is moderate, about 60–70% initially. The protective effect against a mild form of disease falls to about 40% within two months.

Having previously had coronavirus disease also seems to provide good protection against serious coronavirus disease (88%), although the protection against mild infection has fallen due to omicron (56%).  

“With the state of things caused by the omicron variant, both vaccinated people and people who have previously had coronavirus will have a high number of mild cases. According to preliminary studies, however, the disease caused by omicron results in 60% less severe cases irrespective of the vaccines received. Vaccinations still reduce the risk of serious coronavirus disease”, says Hanna Nohynek, Chief Physician at the Finnish Institute for Health and Welfare (THL).  

Vaccines particularly useful for people at risk

By preventing serious cases, coronavirus vaccines clearly reduce the burden on hospitals even with omicron. However, the significance of vaccines in managing the epidemic will be reduced as omicron becomes the mainstream variant. This may lead to many transmissions at the same time, which inevitably increases the need for hospital care.  

“Vaccines are particularly beneficial for people at high risk of serious coronavirus disease. The protection provided by the third vaccine dose is particularly important for people over 60 and other people at risk, but the burden on hospitals can also be alleviated by administering first and second doses to unvaccinated people”, says THL Medical Specialist Eero Poukka.  

“People who aren’t in any risk group and people under 60 who have been vaccinated twice are unlikely to benefit from the third dose as significantly, especially before five months after the second dose. This group is overall at a clearly lower risk of severe disease, so the third doses administered to them will only have a small impact on reducing the burden on hospitals”, Poukka adds.  

Further information: 

Hanna Nohynek 
Chief Physician 
THL 
[email protected] 
 
Eero Poukka 
Medical Specialist 
THL 
[email protected]