ARCHIVED - Second dose of AstraZeneca vaccine brought forward for 60 to 69 year olds in Spain

The interval between doses is shortened from 12 to 8 weeks in response to the spread of the Delta variant

The latest surge in coronavirus infection rates in Spain has so far been concentrated largely in younger adults under the age of 30, due to the prioritization in the immunization campaign of vaccines for those in other age groups, but there is great concern that those in their 60s could also be at risk over the coming weeks as an unforeseen consequence of various decisions which have been made over recent months and of the spread of the Delta variant.

A further 14,137 cases were confirmed yesterday, bringing the total since the pandemic reached Spain to 3.88 million, and the latest increase in the incidence rate comes in sharp contrast to the figures from a year ago: on 7^th July 2020, the reported incidence rate was just 10.01 cases per 100,000 inhabitants.

So, to put it in plain English; the Covid rate is now 22 times higher than a year ago, a week after Spain emerged from the first state of emergency and lockdown.

The full breakdown of 14-day rates by age groups per 100,000 of population in the Tuesday bulletin is as follows, all of them higher than the previous day, but clearly highlighting the concentration of cases amongst younger people:

Age 0-11: 105

Age 12-19: 653 (maximum 2,009 in Navarra)

Age 20-29: 717 (maximum 1,783 in Catalunya)

Age 30-39: 274

Age 40-49: 149

Age 50-59: 79

Age 60-69: 67

Age 70-79: 28

Age 80+: 34

The principal cause for concern at the moment is that most 60-somethings have been given the AstraZeneca vaccine, and although they received their first doses before those in younger age groups the interval before the second dose was set at twelve weeks (rather than four weeks, for example, in the case of Moderna or Pfizer). As a result, more people are still waiting to complete their vaccination course in the 60-69 group than among those in their 50s.

This is illustrated by the latest data published on Tuesday evening by the Ministry of Health. As of 6^th July as many as 94.5 per cent of people aged 60-69 have received at least one vaccine dose (5,045,636 people), but the proportion to have been fully vaccinated is only 57.6 per cent (3,071,643) so this leaves nearly two million people in this age group vulnerable.

Among those in their 50s, by way of comparison, fewer people have received the first dose (88.6 per cent) but far more are fully vaccinated (79.6 per cent).

The real problem lies with the level of immunity after only one vaccine and the spread of the Delta variant.

Data published by Public Health England on June 14 showed that after two weeks for both Pfizer and AstraZeneca, a first dose gave around 50 per cent immunity against the Alpha variant, which is dominant in Spain, but against the Delta variant this immunity fell to 36 percent for Pfizer and only 30 percent for AstraZeneca.

A second dose increased the immunity against the Alpha variant after two weeks to 94 per cent for Pfizer, but only 88 per cent in the case of the Delta variant. For AstraZeneca the protection was 74 per cent for the Aplha variant and 67 percent for the Delta variant.

In both cases, the data put out by the UK Govt. says that the Pfizer vaccine is "96% effective against hospitalisation" and the AstraZeneca "92% effective against hospitalisation" after 2 doses, in relation to the Delta variant.

So this effectively means that all those in Spain who have only received a first dose are still vulnerable.

In response to the perceived risks from the latest rise in infections, and in response to pressure from several regional governments, it was decided by the Ministry on Tuesday that the second dose of the Astra Zeneca vaccine will now be administered 8 weeks after the first, rather than 12. This will mean that many people in their 60s will be given their second dose sooner than they had been expecting.

The Ministry’s figures suggest, at least, that the required doses are in stock. So far, 5.05 million people in Spain have received the first AstraZeneca dose and 2.85 million the second dose, leaving a further 2.2 million awaiting the second jab.

At the same time, Spain has received 10,387,100 AstraZeneca doses and 7,827,597 have been administered, leaving another 2.56 million available even if no more were to be delivered.

There have been continued problems with supply of the AstraZeneca vaccine (as there has been with Janssen) and Spain is now focusing on the Pfizer vaccine as its main source of supply. The EU has, in turn, broken the AstraZeneca supply chain by seeking legal recourse as a result of the delivery shortfalls.

To date, Spain has administered 31.3 million Pfizer vaccines, compared to 4 million from Moderna, 7.8 million from AstraZeneca and 1.3 million from Janssen.

The main reason behind the delay relates back to the decision to "use up" the AstraZeneca stocks on the 60-69-year-old age group after the product was found to be related to a number of instances of blood clots in younger people. Originally Spain had begun administering the AstraZeneca vaccine to those aged under 50 who were working in professions deemed to be "at risk" such as teachers, police, firemen etc, but following the publicity given to the topic of the blood clots, took the decision to stop administering the vaccine to anyone aged under 50.

After weeks of argument and indecision about whether to administer the second dose of the same vaccine to these individuals or permit them to mix vaccines and choose another, the health authorities finally caved in to pressure from the regional governments and authorised the use of Pfizer as a second vaccine. In the end, many users opted to receive their second dose of AstraZeneca rather than taking a second Pfizer dose.

Five deaths in Spain have been linked to the AstraZeneca vaccine, all in the under 50s.