Are some anti COVID-19 vaccines more effective than others?

It is clear that vaccines against COVID-19 have been shown to be highly effective, but is it true that some are more effective than others?.

Woman getting a vaccine in her arm

In the midst of the largest vaccination plan in human history due to the covid-19 pandemic, the question has arisen as to whether there are more effective vaccines than others. Photo: Freepik

LatinAmerican Post | Vanesa López Romero

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Leer en español: ¿Qué tan cierto es que hay vacunas más efectivas que otras?

In the midst of the largest vaccination plan in human history due to the Covid-19 pandemic, the question that has arisen is if whether there are more effective vaccines than others. So far, different media have ensured that the most effective vaccines are Sputnik V (91.6% effective), Pfizer / BioNTech (95% effective) and Moderna (90% effective against COVID-19) .

However, it should be noted that these percentages come from interim analyzes, but as such, there have been no comparisons between vaccines to see if some are more effective than others . In addition, experts have pointed out that while all vaccines are effective, there are some that have been shown to be effective in reducing contagion, while others are effective in reducing the rate of hospitalization and deaths.

But again, keep in mind that these claims have been made since before vaccines began to be administered around the world. That is, they are claims made from analyzes performed before the vaccination process was tested in the real world . In addition, the percentage of the effectiveness of the vaccines in these previous studies also depends on how widespread the Covid-19 variants are in the geographic space where they are administered and on the severity of the disease.

For example, the Johnson & Johnson vaccine was 66% effective against moderate to severe disease in an international study. But it was 72% effective in the United States, where the variants were not as widespread as in other countries .

Another case is AstraZeneca, whose effectiveness has been highly questioned. But in a study carried out by the UK Health Ministry in May this year it was found that both doses of this vaccine provide between 85 and 90% effectiveness against the disease .

Also read: How coronavirus aerosols travel through our lungs

Recently, a study was conducted by researchers in the United States involving more than 4,000 individuals. In this the effectiveness of the Pfizer and the Moderna vaccines was tested. The data showed that both were 91% effective with 2 doses and that the effectiveness was reduced to 81% with only one dose . In this same study, Pfizer and AstraZeneca are found to be highly effective against the Delta variant of the coronavirus.

So, are there some more effective ones?

In the light of the studies carried out, we could affirm that there are, but it is evident that analyzes are needed where vaccines are tested based on comparisons. What is true, and what experts have affirmed, is that all approved vaccines have been shown to protect those who are vaccinated from serious disease, reducing infections, but especially the rate of hospitalization and death . This is extremely important because it precisely allows the reduction of people who are in ICU and, in that order of ideas, infections and red alerts are reduced.