See side effects of the bivalent vaccine against Covid – 03/04/2023 – Health

The bivalent vaccine against Covid started to be applied in Brazil last Monday (27). Formulated with the original variant from Wuhan and the omicron variant, which is predominant in the world, Pfizer’s updated version showed greater protective capacity against infections, hospitalizations and deaths in studies.

In clinical studies around the world, the vaccine has been shown to be safe and effective.

In the United States, according to data from the CDC (Center for Disease Control and Prevention), with more than 22 million doses applied, the side effects reported by about 211,000 people (or 1% of those immunized) were generally mild to moderate. , disappearing within 24 hours.

More than half reported pain at the injection site, while only 1% said medical attention was required.

Also according to data from the CDC, the updated vaccine was 48% effective against infections caused by XBB/XBB.1.5, omicron subvariants, (against 52% for BA.5) in people aged 18 to 49 years.

In older individuals, aged 50 to 64 years, prevention was 40% against XBB/XBB.1.5 (43% against BA.5) and 43% in people aged 65 years or older (against 37% for BA. .5).

Specialists argue that the monovalent vaccines still have a high efficacy of protection against hospitalizations and deaths, mainly in younger individuals, but that reinforcement with the bivalent vaccine is important for older people, mainly those with 70 years or more, and who already for a long time without updating the reinforcement, in the case of Brazil.

See below what are the main side effects that may arise with the bivalent.

What are the most common side effects with the bivalent vaccine?

In general, the updated omicron vaccines maintain the same safety standard as the monovalent forms already authorized and used by billions of people around the world.

Bivalent doses have been reviewed and approved by regulatory agencies around the world, which have proven their safety and efficacy as a vaccine booster.

In Brazil, bivalent vaccines are only being applied to the target public, which is people over 60 years old and immunosuppressed, in this first stage (above 70 in some places, such as in the capital of São Paulo), and in pregnant women, mothers and health professionals in the next steps.

In general, the most common effects that have been reported are pain at the injection site, fatigue, headache, body aches (myalgia), fever and chills.

Such effects have also been reported with boosters of monovalent vaccines and are considered mild, with symptoms disappearing within 24 hours.

Health professionals are advised at vaccination posts to monitor the intensity of the effects and, if necessary, to use common analgesic drugs for treatment.

Other less common side effects considered moderate to severe may include myocarditis (inflammation of the myocardium), pericarditis (inflammation of the pericardium), chest pain, shortness of breath, and arrhythmia.

It is important to note that these effects were extremely rare, with only five cases of myocarditis and four of pericarditis being reported among all over 22 million vaccinated in the US, or less than 0.0000025%.

There was also a report of a serious adverse event with a patient who took the bivalent vaccine together with the flu and suffered a cerebrovascular accident (CVA), but the investigation conducted by the CDC concluded that the event was not related to the vaccine.

Why should I receive the bivalent vaccine?

The updated vaccine offers greater protection to the omicron subvariants currently in circulation. This protection can be even more effective in people considered to be in a higher risk group, such as immunosuppressed people, the elderly, pregnant and puerperal women.

Monovalent vaccines, which were used in the entire population over 12 years of age, are still highly effective in protecting against hospitalization and death, but protection ends up decreasing over time. That’s why it’s important to get vaccine boosters every three to four months, experts say.

In the case of the elderly, even with monovalent vaccines, the risk of hospitalization is still greater than in young and healthy people, so the importance of updating with the bivalent vaccine is fundamental.

Are there any contraindications to receiving the bivalent?

In clinical studies and analyzes of real-life use of bivalents, no risks associated with receiving the bivalent booster that could contraindicate its application were found.

There is also no contraindication to receiving the Covid vaccine in conjunction with other vaccines, such as the flu. Updating vaccination with boosters can be done after four months since the last vaccine applied.

If I don’t receive the bivalent now, am I unprotected from Covid?

In general, the bodies of people who received at least three doses of the Covid vaccines continue to offer protection against hospitalization and death, although protection against infection or reinfections (the possibility of having a new infection with the virus more than once) may be reduced.

It is important to note that updated vaccines offer greater protection compared to neutralizing antibodies, which are those designed to block the entry of the Sars-CoV-2 virus into our body’s cells.

In this way, a new reinforcement recovers the levels of neutralizing antibodies, which have a natural decay over time and can be affected by the mutations found in the new variants.

But there is another type of protection induced by our immune system, which is cellular immunity, produced by lymphocytes or T cells. These cells are involved in building the memory immune system and are quickly programmed to attack the invader when it enters our body. .

Experts claim that the protection of these cells lasts longer, even capable of responding to new forms of the virus in circulation, since it tends to be less specific in relation to the mutations that may arise.