2 Years of Covid Vaccines: What We’ve Learned About Outcomes and Side Effects

The London Science Museum, in the United Kingdom, has set up a temporary exhibition to mark the epic development and application of vaccines against Covid-19 in record time.

On one of the shelves, you can see the syringe, ampoule and cardboard tray that were used on December 8, 2020, when 90-year-old Englishwoman Margaret Keenan became the first person to receive the Covid vaccine. -19 outside of clinical studies.

Since then, another 13 billion doses have been administered worldwide, including boosters and updated immunizers, which protect against the latest variants.

What have we learned in these two years of campaigning? What do the data reveal about the effectiveness of immunizations? And what is known about the side effects?

In summary, studies show that tested and approved Covid vaccines were primarily responsible for containing hospitalizations and deaths from infection-without them, the numbers affected by the health crisis would be much greater.

In addition, the most serious adverse events are considered rare by public health institutions.

the practical effects

“Vaccination against Covid made the difference between dying and surviving for many people”, summarizes doctor Isabella Ballalai, vice president of the Brazilian Society of Immunizations (SBIM).

Since doses began to be applied to the majority of the population, hospitalization and death rates from complications related to the coronavirus have dropped considerably.

And even with the arrival of more transmissible variants such as omicron, immunization ensured that most people did not become severely ill or die.

Brazil is an example of this: when the first vaccines were approved by the National Health Surveillance Agency (Anvisa) in January 2021, the country was about to experience the most serious moment of the entire pandemic.

Between late March and early April last year, the daily moving average of deaths from Covid surpassed 3,000 (with records of 72,000 new infections/day), according to the National Council of Health Secretaries. (Conass).

As the weeks went by — and the percentage of Brazilians vaccinated increased — the numbers began to drop little by little.

This statistic only rose again in January 2022, with the arrival of the omicron variant. Even so, the peak of this wave was 950 daily deaths, while the number of new infections reached 189,000 every 24 hours.

To make the comparison clearer:

• March/April 2021 wave peak: average of 75 thousand cases and 3 thousand deaths per day.
• January/February 2022 wave peak: average of 189 thousand cases and 950 deaths per day.

Another indication of the effectiveness of vaccines comes from a survey published on December 13th.

In it, the Commonwealth Fund asked scientists at the School of Public Health at Yale University, in the United States, to try to answer a question: what if we didn’t have vaccines against Covid-19 until now?

The results found indicate that the US alone would have faced 18.5 million hospitalizations and 3.2 million additional deaths from Covid in the last two years.

In addition, the American vaccination program represented savings of US$ 1.15 trillion in medical costs, which would be necessary to pay for the treatment of extra cases of the infection.

“Since December 2020, 82 million infections, 4.8 million hospitalizations and 798,000 deaths have been recorded in the country. In other words, without vaccination, the US would have experienced 1.5 times more infections, 3.8 times more hospitalizations and 4.1 times more deaths”, compare the authors.

And the side effects?

“The more time passes and the more doses of Covid vaccines are given, the more we are sure about their safety profile,” Ballalai replies.

In these two years, regulatory agencies and public health institutions make a great effort to monitor and investigate each case of probable post-vaccination adverse event.

The UK National Health Service (NHS) points out that “serious side effects are very rare”.

Among the most common discomforts after vaccination, they highlight:

• Pain at the injection site;
• Feeling tired;
• Headache;
• Body ache;
• Fever;
• Feeling unwell or sick.

The entity details that “most of these side effects are mild and should last less than a week”.

“If you have a high temperature for more than two days, a continuous cough or you lose your sense of taste and smell, you could have Covid-19”, guides the NHS.

“You don’t get Covid from the vaccine, but it is possible to have become infected shortly before or after receiving the dose”, adds the article.

But what about serious adverse events? What do the latest numbers say?

The most up-to-date record of such statistics is published by the US Centers for Disease Control and Prevention (CDC).

In a publication, the entity points out the proportional number of cases of the most serious side effects known so far:

• Anaphylaxis (severe allergic reaction after vaccination): 5 cases per 1 million doses applied;
• Janssen Vaccine Related Thrombosis: 4 cases per 1 million doses applied;
• Janssen vaccine-related Guillain-Barré syndrome: there is no fixed number, but there has been a small increase in cases in men over 50 immunized with this product compared to those who received doses of Pfizer;
• Myocarditis and pericarditis (heart inflammation) in young people who took the Pfizer vaccine:
• From 12 to 15 years old: 70.7 cases per million applied doses;
• From 16 to 17 years old: 105.9 cases per million doses applied;
• From 18 to 24 years old: 52.4 cases per million doses applied.

The CDC reports that “most patients who had myocarditis and pericarditis after vaccination against Covid-19 responded well to treatment and rest and felt better quickly.”

The entity reaffirms that “multiple studies and reviews of data from safety monitoring systems continue to show that vaccines are safe”.

Regarding deaths, American records calculate that, of the 657 million doses administered there until December 7, 2022, 17,800 deaths were identified after vaccination (or 0.0027% of the total), even if the application of the doses were not identified as the direct cause of this. Investigation of all these cases through analysis of medical records and autopsies found only nine deaths associated with the use of the Janssen vaccine there.

Ballalai recalls that no medicine, vaccine or procedure is risk-free. “All these data show us that the cost-benefit of vaccinating far outweighs the eventual and rare problems”, she concludes.

What lays ahead

Two years after the first vaccines against Covid-19 became available, there are still many challenges to effectively control the coronavirus.

“From a global point of view, we have countries that are far behind in immunization”, highlights epidemiologist André Ribas Freitas, scientific consultant for A Casa, a platform that brings together national health agents and agents to combat endemic diseases.

In Haiti, for example, only 2% of the population took the two initial doses. The numbers are also low in countries like Algeria (15%), Mali (12%), Congo (4%) and Yemen (2%).

“This represents a very big concern, since the maintenance of intense viral transmission represents a risk for the emergence of more transmissible or pathogenic variants”, warns the specialist, who is also a professor at the São Leopoldo Mandic Medical School, in Campinas, in the interior paulista.

Brazil also has its own challenges and routes to correct over the coming months, experts point out.

“Some scholars calculate that up to 300,000 lives could have been saved if we had started vaccination earlier and at full speed”, regrets Soraya Smaili, professor of pharmacology and former dean of the Federal University of São Paulo (Unifesp).

Data compiled by the CoronavirusBra1 portal reveal that 81% of Brazilians have taken the initial vaccination schedule so far.

The number of individuals who received booster doses, essential to protect against the omicron variant, is much lower: only 56% of people have their immunization schedule properly updated.

In addition to increasing this vaccination coverage, health professionals heard by BBC News Brasil point out two other frontiers that the country will need to pay attention to in the coming months: the protection of children and the application of bivalent doses (which protect against the most recent variants) in priority groups, such as the elderly and immunosuppressed.

“One of these updated bivalent vaccines has already been approved by Anvisa and is administered in the United States and Europe. We need it right away, mainly to protect those most vulnerable to complications from Covid”, points out Smaili.

Ballalai points out that these updated immunizers should be restricted precisely to these specific groups. “The ‘original’ vaccines that we have today continue to protect the rest of the population well,” she says.

Freitas, in turn, understands that the immunization of children should be a top priority. “Vaccination coverage against Covid among younger Brazilians is very low”, he points out.

Although deaths among children are less frequent, the absolute numbers are alarming: the Oswaldo Cruz Foundation (FioCruz) calculates that Brazil recorded one death of children aged 6 months to 5 years per day throughout the entire year of 2022.

“Although we are in a much more favorable scenario, the pandemic is not over yet and between 80 and 100 Brazilians still die every day”, highlights Ballalai.

“And having up-to-date vaccinations is the best strategy to be more protected”, concludes the doctor.

This text was originally published here.