Professor Anita Villeruša: Booster Vaccines Mobilise the Immune System
Both in Europe and elsewhere in the world, morbidity rates are rising rapidly and there are concerns about a new coronavirus wave due to the spread of both the Delta virus and the new variant – Omicron.
Data from countries where the majority of the population has already received a third dose of the vaccine shows that this increases the body's immune system, and that booster vaccines are a good way to reduce the risk of a symptomatic and severe course of the disease. We met with Anita Villeruša, Professor at Rīga Stradiņš University (RSU) and member of the National Immunisation Council, to learn more about the importance of a third dose of the vaccine.
Why do we need a third dose?
Global long-term studies on changes in vaccines’ efficiency have shown that effectiveness starts to decrease approximately six months after the last vaccine has been administered, primarily the effectiveness at preventing a light or asymptomatic course of the disease.
Vaccines’ efficacy at preventing the risk of hospitalisation is better preserved.
By getting a booster vaccine, we mobilise our immune system and increase its ability to respond to the virus.
Who can get a booster?
Studies show that all people over the age of 40 should get a booster.
People will be getting their booster doses gradually, since the date when the person in question last received their final vaccine is important.
The basic principle has been to start with people for whom getting sick with COVID-19 would pose a heightened risk. This includes the elderly and people with various severe chronic diseases. Booster vaccines are being administered according to a similar principle.
In general, booster vaccines are currently available for anyone in Latvia starting from the age of 18, yet it is important to consider how long it has been since the full vaccination course was completed.
Risk groups, such as the elderly, people with chronic diseases (cardiovascular, renal and oncological diseases, diabetes, obesity, immune system disorders, etc.), are particularly welcome to receive their boosters. People who are at increased risk of coming into contact with an infected person during the course of their professional duties are also required to receive a booster dose.
It is recommended that people who have had a Pfizer or Moderna vaccine (known as messenger or mRNA vaccines) receive their booster six months after their last vaccine. Those who had the AstraZeneca vaccine (known as a viral vector vaccine) this time interval is five months, as studies show that this vaccine is less effective. Whereas the Janssen vaccine, which is also a viral vector vaccine and requires only one dose, has the lowest efficacy. Those who received the Janssen vaccine are recommended to receive their booster dose already eight weeks after receiving the first.
Where can people find more information about booster vaccines?
All information is available at ManaVakcīna
Note that if the required time has not yet passed, you will not be able to apply for a third dose.
Is there a group of society that shouldn't get a booster dose?
As with primary vaccination, some it is possible that some people may experience reactions or side effects after receiving a booster dose. In case of a severe reactions, visit your GP. Booster vaccines are not required for people who have been fully vaccinated and have subsequently been infected with the virus (this should be confirmed by a positive COVID-19 PCR test). In these cases, the body’s immune system has already been mobilised and there is no need for an additional dose. In case of any concerns about medical contraindications to the booster vaccine, experience shows these are similar as for previous shots. Sometimes it is necessary to consult a doctor, as there can be medical reasons for postponing a booster vaccine.
What vaccines are used as boosters? Is it possible to choose?
It is primarily recommended to receive mRNA vaccines as boosters – i.e. Pfizer or Moderna. Both these vaccines are also offered at vaccination sites.
Will people’s vaccination certificates change after receiving a booster dose?
The certificates will be updated. After the primary vaccination, people received a certificate that remains valid after receiving the third vaccine. The certificate provides information on the time of the third vaccine and the type of vaccine administered. According to regulatory enactments, anyone can get their new certificate 15 days after receiving their booster, and both certificates remain equally valid.
