The latest coronavirus wave in Spain: what the statistics tell us so far

Covid-19 cases have been rising exponentially in Spain once more since the end of June, with new infections doubling each week. The pandemic is in a different phase, thanks to the vaccination campaign, but concerns are rising for two reasons: the speed of the spread – above all among young people – and hospital admissions, which are also going up. A number of Spanish regions have already toughened up their restrictions.

This worsening situation can clearly be seen in the following graph, which has a linear scale and a logarithmic one to better illustrate the progress of the pandemic. Right now, both infections and hospital admissions are growing exponentially and are doubling every few days.

The best news is that hospitals are not experiencing this fifth wave in Spain as they did after the Christmas holiday season. While cases have shot up and are close to the worst figures from January, admissions are far from what they were back then. In the first month of the year, there were 20 to 70 daily admissions of Covid-19 patients for every 100,000 inhabitants, while the current number of hospitalizations is around 10 for every 100,000 inhabitants.

This decoupling of cases and admissions is being driven by two factors. On the one hand, it appears that being fully vaccinated reduces the probability of requiring hospitalization in the event of catching the virus and developing symptoms, as research from the United Kingdom suggests. But above all, the decoupling is due to the high vaccination rates among older people, who are more susceptible to Covid-19 and thus are more likely to require hospital treatment.

Currently, typical cases are among young people, which is why the rate of admission has fallen. The situation in hospitals is different, as Antoni Trilla, an epidemiologist and doctor at Barcelona’s Hospital Clínic, explains. “There are fewer Covid patients, above all in the ICU [intensive care unit], and that is why there are fewer cases among patients with risk factors. Patient management is still normal, and although there will always be some complicated cases, the impression is that they are having better outcomes.”

The epidemic, by age

One of the keys right now is that older people are seeing fewer infections. The over-70s, who are nearly all fully vaccinated, have infection rates of around 75 cases per 100,000 inhabitants over 14 days. This is the best news: Covid-19 deaths fall drastically when older people are not getting the virus, which is much more serious for these age groups.

However, a conclusion can be drawn from the data for this group: for now, the percentage of people infected who end up in hospital has not fallen much despite the vaccination campaign. Nearly 25% of those aged over 80 who get infected end up needing hospital treatment (that is the ratio between admissions today and cases from a week ago), which is a lower rate than that seen in recent months, but not much lower.

The graphs below show the data for each age range: the number of infections that are being detected in that group and the percentage of hospital admissions that are registered for every case.

To sum up, the sensation is that seniors are protected, but not so much because they are not being admitted to hospital but rather because they are not getting infected. If infections rise, these data indicate that admissions will do so quickly too. In Catalonia, for example, as we can see below, hospitalizations of seniors are also rising. As pointed out by Gonzalo Tamayo, a specialist in anesthesiology and resuscitation at Cruces Hospital in Bizkaia, “the severity of the disease continues to be determined by the same risk factors: age, hypertension and cardiovascular disease are the most important.”

The conclusions are similar for those aged 40, 50 or 60: it is fundamental to see how the incidence progresses in these groups. Right now, cases are rising, with relatively low incidences, from 300 cases for 40- to 49-year-olds to 150 for the 60-69 group, due to a mixture of the vaccination – partial for the latter group still – and also due to more caution.

But patients in these age groups continue to be admitted to hospitals: this is the case for around 5% of cases aged 45, 6% aged 55 and 10% aged 60 to 69. In these age groups, the vaccine is a race to slow infections, which right now are threatening to dangerously spike.

Among young people, the situation is dominated by the low levels of vaccination. This group is in a worse situation right now than at any other time during the pandemic: there are a few people vaccinated, but not enough to make a difference to the more-contagious delta variant, which is spreading fast at a time when restrictions are being lifted and social interactions are rising.

The 20-29 group currently has a 14-day cumulative number of coronavirus cases per 100,000 inhabitants of 1,500, a figure that soon could exceed the worst levels seen in January. Young people are very unlikely to need hospital treatment – the figure is one or two admissions for every 100 cases detected. That risk is small, but it is greater than it was over the last year. The probability of a 20- to 29-year-old being taken into hospital with Covid-19 is now greater according to data for the last week than at nearly any other time in the last year. As Tamayo explains, “the fact that the incidence of serious illness is lower does not mean that it is zero. And with a cumulative incidence of nearly 1,000 cases per 100,000 among 20- and 30-year-olds, some will develop serious illness.”

More detail can be found for some regions, such as Catalonia, which offers a daily update on the ages of Covid-19 patients admitted to hospital. Here it can be seen that hospitalizations are rising for all ages. In the last week, there were 100 daily admissions for people over 80 and 170 for the 60-69 age group. Every day saw 200 admissions of patients aged 40 to 49, which is one of the worst figures since data collection began. Hospitalizations of the 30-39 group are at around 180, which is double the worst figures from the fall. Figures for 20- to 29-year-olds are at around 80, which is triple the previous highs.

The good news is that the total figures are far from the worst of the pandemic, given that the number of seniors being admitted to hospital is much lower. Admissions of the over-80s are one-seventh what they were in the fall and winter; those for the 50-59 group are a third.

The situation also differs from region to region. The worst incidence levels among youngsters are to be found in Castilla y León, Catalonia, Asturias, Navarre and Cantabria. There, between 2% and 4% of all 20-to-29-year-olds have been infected in the last two weeks. The incidence falls with age, but in general the regions with the worst figures among youngsters also have the highest data for people aged over 40, 50 and 60.

The question now is how this situation is going to progress. With cases and admissions that are doubling every week, the figures could quickly get worse. This could also happen in age ranges that have been vaccinated, and in particular those that are half-vaccinated. After several weeks now with fewer coronavirus restrictions across Spain, and based on the trend in infections, Trilla says that “the percentage of cases that are admitted [to hospital] could increase in the coming days in the age ranges with low vaccination rates.” This dynamic could worsen the situation very quickly. The hope is that the propagation of the virus slows or there is a change in trend, whether it be because measures are taken, because individual protections are stepped up, or, as is happening among young people, because high percentages of the population are contracting the disease.

English version by Simon Hunter.