Infected 50-69 year olds double in just one week

Half of the 60-year-old population has not received the second dose yet

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Mobile vaccination campaign will be carried out on buses and trucks

BarcelonaThe boom in infections among young people has led to the transmission of covid to all age groups and is already causing the first collateral victims in some vulnerable age groups. The incidence of the virus among the population over 50 has doubled in just a week, mostly among unvaccinated people or those who have not yet received the second dose and are not fully immunised, according to the Department of Health. In the 50-59 age group, Catalonia has gone from registering 47 cases per 100,000 inhabitants on 30 June to the current 114 cases. In the same period of time, in those who are 60 to 69, the rate has grown from 46 infections per 100,000 inhabitants to 103.

Although the increase is evident in both age groups, sexagenarians are the ones that most concern the health authorities because of their vulnerability to infection: from this age onwards the immune system begin to be weaker and does not respond as well to vaccines and, in case of infection, these people are more likely to be admitted to hospital and suffer severe covid. Unfortunately, however, this is the group that is taking the longest to get vaccinated.

Their immunisation began last March, but many of them still do not have the full regimen: only 62.6% of people aged between 60 and 65 and 51% of those aged between 66 and 69 have received the second dose and are considered to be fully vaccinated. The reasons why this process is taking so long in this age group are, on the one hand, the continuous changes in criteria regarding which vaccine they should receive -until a few weeks ago only AstraZeneca was administered- and, on the other hand, the changes in the period of time that should be left between doses.

At first, they followed the technical data sheet of the Anglo-Swedish preparation and waited the 12 weeks set by the laboratory. With the threat of the delta variant, however, the Ministry of Health authorised autonomous communities to reduce this spacing to 10 weeks and now, at most, the Department of Health has decided to inoculate them in the eighth week from the first dose.

These obstacles have hindered the immunisation of one of the most vulnerable groups and the effects of this brake begin to materialise in the form of admissions to intensive care units (ICU): most patients admitted to the ICU are people between 40 years old (which less than a month ago began to be vaccinated) and 69. Most of the cases correspond to unvaccinated people, but there are also a few cases among people with the full vaccination regimen, says the Health minister, Josep Maria Argimon.

Highly effective

"It has to be very clear that the vaccines against covid are also excellent against the delta variant and as proof we have the evident reduction of deaths and hospitalisations despite the explosion of cases in recent weeks. However, from the age of 65 onwards, immune systems may respond less well to vaccine stimuli, as also happens with people with serious diseases such as cancer or immunosuppressed people", explains Gemma Moncunill, immunologist and researcher at the Institut de Salut Global de Barcelona (ISGlobal).

The expert points out, however, that it is essential to comply with the vaccination schedule in order to protect the population. Vaccines do not have a direct and immediate effect on the immune system, but stimulate it indirectly. In double-dose schedules, as in three of the four covid vaccines, the first dose is often called the "memory" dose because it has a limited effect and antibodies decline over time, while the second is called the "booster or reminder" because it brings these defenses back up and stabilises them at higher levels.

Recently, a study carried out in Israel, where the vaccination campaign was based exclusively on Pfizer inoculation and where the delta variant is already predominant, has lowered the vaccine's effectiveness data: preliminary results indicate that it would be 64% compared to the initial 94% in the case of preventing infections and symptomatic diseases, but it is still highly effective (93%) in preventing serious infections and, therefore, hospitalisations, ICU admissions and deaths.

Indeed, all vaccines licensed by the European Medicines Agency (EMA) - Pfizer, Moderna, AstraZeneca and Janssen - are effective in preventing the serious consequences of covid. Full vaccination with Pfizer and Moderna prevents infection in 90% of severe cases, symptoms in 95% of cases, and hospitalisation and death in 99% of cases. As for AstraZeneca, with two doses, the development of the disease is prevented in 85% of cases and admissions and deaths in 99% of cases.

The Health Minister has also made it clear that vaccines are very effective, but they are not infallible; that is, they do not protect everyone at the same level. In fact, it is estimated that 10% of those vaccinated may not develop immunity and, therefore, could be susceptible to symptoms if infected or even become severely ill. The more covid transmission increases, the greater the risk that these people will suffer severe illness if they become infected.