Covid-19 vaccines: What are the risks and benefits for each age group? – EL PAS in English

All licensed vaccines are extremely effective in preventing severe cases of Covid-19, a disease that has killed around three million people worldwide in the space of one year. However, there are still individuals who are more afraid of the vaccine than of the virus. The focus now is on the Oxford-AstraZeneca and Janssen vaccines, after dozens of those who were vaccinated about 1 in 100,000 developed a very rare form of potentially lethal blood clots.

Below is a sample of risk-versus-benefit calculations. While approximate, they are useful for understanding the kind of figures used by drug regulatory agencies. We start by looking at a general scenario of 100,000 adults of all ages over a period of four months with an incidence of Covid-19 that reflects the rates experienced in 2021 in Spain:

If 100,000 people dont get vaccinated, around 3,800 people will become infected

If 100,000 people do get vaccinated, around 950 people will become infected

Fewer infections

If 100,000 people get vaccinated, around 2,850 people will avoid catching Covid-19 in this example. And thats without taking into account the fact that getting vaccinated will also put the brakes on transmission.

If 100,000 people dont get vaccinated, around 250 will end up in hospital

If 100,000 people do get vaccinated, around 13 will end up in hospital

Far fewer hospital admissions: the vaccine will prevent 237 hospitaliza- tions (19 out of 20 or more)

If 100,000 people do get vaccinated, around 2 will be admitted to an ICU

If 100,000 people dont get vaccinated, around 25 will be admitted to an ICU

The admissions to ICUs will be one or two, if not fewer, instead of 25.

If 100,000 people do get vaccinated, around 3 will die

If 100,000 people dont get vaccinated, around 60 will die

57 people

(out of 100,000)

will avoid death

One serious

case of

thrombosis

From a sample of 100,000 people vaccinated, over the space of four months one person will develop thrombosis

But around 20 ICU cases and between 50 and 60 deaths will have been avoided

Note: In this scenario, we have assumed a 3.8% infection rate in Spain which is the rate registered between January and now; also that the vaccine is 75% effective.

If 100,000 people dont get vaccinated, around 3,800 people will become infected

If 100,000 people do get vaccinated, around 950 people will become infected

Fewer infections

If 100,000 people get vaccinated, around 2,850 people will avoid catching Covid-19 in this example. And thats without taking into account the fact that getting vaccinated will also put the brakes on transmission.

If 100,000 people dont get vaccinated, around 250 will end up in hospital

If 100,000 people do get vaccinated, around 13 will end up in hospital

Far fewer hospital admissions: the vaccine will prevent 237 hospitalizations (19 out of 20 or more)

If 100,000 people do get vaccinated, around 2 will be admitted to an ICU

If 100,000 people dont get vaccinated, around 25 will be admitted to an ICU

The admissions to ICUs will be one or two, if not fewer, instead of 25.

If 100,000 people dont get vaccinated, around 60 will die

If 100,000 people do get vaccinated, around 3 will die

57 people

(out of 100,000)

will avoid death

One serious

case of

thrombosis

From a sample of 100,000 people vaccinated, over the space of four months one person will develop thrombosis

But around 20 ICU cases and between 50 and 60 deaths will have been avoided

Note: In this scenario, we have assumed a 3.8% infection rate in Spain which is the rate registered between January and now; also that the vaccine is 75% effective.

If 100,000 people dont get vaccinated, around 3,800 people will become infected

If 100,000 people do get vaccinated, around 950 people will become infected

Fewer infections

If 100,000 people get vaccinated, around 2,850 people will avoid catching Covid-19 in this example. And thats without taking into account the fact that getting vaccinated will also put the brakes on transmission.

If 100,000 people dont get vaccinated, around 250 will end up in hospital

If 100,000 people do get vaccinated, around 13 will end up in hospital

Far fewer hospital admissions: the vaccine will prevent 237 hospitalizations (19 out of 20 or more)

If 100,000 people do get vaccinated, around 2 will be admitted to an ICU

If 100,000 people dont get vaccinated, around 25 will be admitted to an ICU

The admissions to ICUs will be one or two, if not fewer, instead of 25.

If 100,000 people do get vaccinated, around 3 will die

If 100,000 people dont get vaccinated, around 60 will die

57 people (out of 100,000)

will avoid death

One serious

case of

thrombosis

From a sample of 100,000 people vaccinated, over the space of four months one person will develop thrombosis

But around 20 ICU cases and between 50 and 60 deaths will have been avoided

Note: In this scenario, we have assumed a 3.8% infection rate in Spain which is the rate registered between January and now; also that the vaccine is 75% effective.

If 100,000 people dont get vaccinated, around 3,800 people will become infected

If 100,000 people do get vaccinated, around 950 people will become infected

2,850 (out of 100,000)

will avoid becoming

infected

Fewer infections

If 100,000 people get vaccinated, around 2,850 people will avoid catching Covid-19 in this example. And thats without taking into account the fact that getting vaccinated will also put the brakes on transmission.

Note: In this scenario, we have assumed a 3.8% infection rate in Spain which is the rate registered between January and now; also that the vaccine is 75% effective.

If 100,000 people do get vaccinated, around 13 will end up in hospital

If 100,000 people dont get vaccinated, around 250 will end up in hospital

237 (out of 100,000) will

avoid hospitalization

Far fewer hospital admissions: the vaccine will prevent 237 hospitalizations (19 out of 20 or more)

If 100,000 people dont get vaccinated, around 25 will be admitted to an ICU

If 100,000 people do get vaccinated, around 2 will be admitted to an ICU

The admissions to ICUs will be one or two, if not fewer, instead of 25.

If 100,000 people do get vaccinated, around 3 will die

If 100,000 people dont get vaccinated, around 60 will die

57 people (out of 100,000) will avoid death

One serious

case of

thrombosis

From a sample of 100,000 people vaccinated, over the space of four months one person will develop thrombosis

But around 20 ICU cases and between 50 and 60 deaths will have been avoided

These approximate calculations are also similar to estimates from the British regulatory agency MHRA. They make it very clear that, irrespective of age, the benefits of the AstraZeneca and Janssen vaccines far outweigh their known risks.

In a scenario such as the above, in which the infection rate is 3.8% over several months, vaccination prevents 50 to 60 deaths and 200 hospital admissions per 100,000 people while triggering just one serious and potentially lethal thrombosis, according to the European Medicines Agency (EMA).

However, the analysis should be carried out according to age as Covid-19 is not as dangerous at 20 as it is at 70. This is why the vaccination campaign was initiated in nursing homes, because the disease is 15 times more deadly at age 55 than at 25.

The following graphic flags up these differences, showing the number of people hospitalized, admitted to intensive care or killed by Covid-19 per 100,000 in each age bracket, assuming, again, that the probability of becoming infected is 3.8% over a given period:

Assumption: a 3.8% probability of becoming infected with Covid-19 at any given moment (without a vaccine).

For the elderly, the difference between being vaccinated and not being vaccinated is massive. Among the over-80s, deaths with the vaccine are reduced from 500 to 25 per 100,000, with no cases of thrombosis expected. These differences are slightly reduced but remain significant in the 70s, 60s and 50s age brackets. For those in their 40s, the vaccine would prevent two or three deaths per 100,000 people, nine intensive care admissions and 100 hospitalizations, but would trigger thrombosis in one person, according to EMA estimates.

The benefits of AstraZenecas Covid vaccine continue to far outweigh the risks for most people, said the head of the British regulatory body, June Raine, referring to the estimates.

However, their calculations, like those made by EL PAS, do pose a dilemma for younger people. On account of this, the British agency proposes vaccinating this demographic with the Pfizer-BioNTech and Moderna vaccines, which have shown no similar side effects so far. The virus is much less dangerous for very young people and, if its circulation becomes minimized, the risk posed by Covid-19 for this group is equal to the risk, also low, posed by the thrombosis associated with the AstraZeneca and Janssen vaccines.

According to EL PAS approximate calculations regarding people in the 20-to-29 age bracket, the vaccine prevents a couple of admissions to intensive care and half a death per 100,000 people, but it is possible that it could cause one or two cases of lethal blood clotting, according to estimates being used by the different regulators.

It is difficult to know at this point the precise risk of thrombosis associated with the vaccines. The estimates are currently under investigation with the possibility that they will be different based on age, gender or other characteristics. In the United Kingdom, authorities estimate a thrombosis risk of approximately one in 250,000 with the AstraZeneca vaccine. They also believe that the risk is twice as high in younger people as in older people, and, although they have found more cases in women, they have not yet published estimates according to gender. The EMA estimates the risk of thrombosis to be one in 100,000, without yet linking that risk to gender or age. In Denmark, they estimate the risk to be one in 40,000.

This is in connection with the AstraZeneca vaccine. However, the US Federal Drug Administration (FDA) has just released a report on the Janssen vaccine, which uses the same delivery mechanism as AstraZeneca. The FDA has found six cases of thrombosis, almost all in young women, among the millions who have been vaccinated, so the incidence in that group could be one in 100,000. But, as US epidemiologist Caitlin Rivers explains, more cases could come to light. This uncertainty explains why regulators are doing more studies: it is logical to be vigilant.

The figures above outline a scenario in which the rate of future infections mirrors the rate recorded over the past four months: 3.8% of the population, or one in 25. But this is only a point of reference. Obviously, the benefit of being vaccinated increases the more at risk you are of infection; if, say, the pandemic lasts for another year.

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Covid-19 vaccines: What are the risks and benefits for each age group? - EL PAS in English