Spain is one of the countries that received the highest percentage of the population with the second dose of the Covid-19 vaccine: 2.4% received two stings, which means that it has full protection offered by the vaccine. According to Our World in Data, run by the University of Oxford in the UK, Spain is just behind Israel – which is the clear leader, with almost a third of the population fully vaccinated – the United States (4.83%), Denmark (2 , 99%), Romania (2.74%) and Serbia (2.67%).
But while this is good news – meaning vaccines are being administered at high speed as they are delivered – there is another side to the coin. Studies show that just one dose of the vaccine can provide a high level of protection against Covid-19. This means that any other dose administered can be considered a stroke that does not go to protect the other person.
The vaccination plant in the United Kingdom follows this principle. Although Spain gave a higher percentage of the population with the second dose than Great Britain, it is far behind the country in relation to the first sting. In Spain, 3.5% of the population received the first dose of Covid, compared to 25% in the UK. This approach by the government of Prime Minister Boris Johnson was initially viewed with skepticism, but an increasing amount of research supported it.
The study was published last Friday in a medical journal Lancet shows that Pfizer-BioNTech is 85% effective in symptomatic infections after the first dose. The investigation, which involved more than 7,000 workers at Sheba Medical Center in Tel Aviv, Israel, found a dramatic reduction in the infection rate between 15 and 28 days after the first inoculation, reports Juan Carlos Sanz. In relation to total coronavirus infections, including asymptomatic cases, Pfizer vaccine was found to be 75% effective. The findings come after two Canadian scientists published a letter in New England Journal of Medicine claiming that the first dose of Pfizer vaccine was 92.6% effective, according to studies by the pharmaceutical company itself and the US administration.
Although Canadian scientists admit that there are doubts about how long protection from one dose lasts, they claim that giving another sting after only a month has fewer short-term benefits. They write: “Given the current shortage of vaccines, delaying the second dose is a matter of national security which, if ignored, will certainly result in thousands of hospitalizations and deaths associated with Covid-19 this winter in the United States – hospitalization and death would be prevented the first dose of vaccine. “
Spain follows the guidelines of the regulatory authorities: administer the second dose when the time comes, according to the vaccine instructions. Amós García Rojas, president of the Spanish Society of Vaccinology, says new studies must be examined as they are published to decide whether this vaccination strategy will change, acknowledging that much can change very quickly depending on new data. But for now, it supports adherence to the protocol established by the European Medicines Agency (EMA), especially given that doses are expected to arrive faster, meaning the population can be vaccinated at a faster rate.
In the case of vaccines developed by Pfizer, the EMA recommends waiting 21 days before a second dose, but recognizes that this period can be extended to 42 days without affecting the effectiveness of the vaccine. These 21 days are not trivial. At the current rate in Spain, 1.3 million people could be vaccinated with the first dose during this period. For Covid vaccines from Moderna and AstraZeneca, it is recommended to wait 28 days and 12 weeks, respectively, before administering the second dose.
Spain has already updated its vaccination protocol once. In response to studies that showed that people infected with the coronavirus developed a strong immune response, the Ministry of Health recommended that an individual wait six months from the date of diagnosis before vaccination.
The effect of the vaccination movement is beginning to show
All signs indicate that Spain is beginning to notice the effects of the vaccination campaign launched in late December. Nursing homes, where more than 90% of residents received two doses, are showing increasing hope. Outbreaks in social service residences have fallen by 75% in the last month, more than halving the decline outside these centers. And a growing number of Spanish regions are reporting declines in new coronavirus cases and Covid-19-related deaths.
One of the clearest cases this fall is Asturias, which was also the Spanish region that vaccinated the residents of nursing homes the fastest. The chart below shows the weekly number of coronavirus victims inside and outside social service residences. While in early 2020 the two categories followed the same pattern, they began to drift apart for three weeks in the instinct of vaccination. The delay is understandable given that the vaccine may take between 10 and 12 days to work and that the number of deaths is the last data point that reflects the decline in infection. But three weeks after the vaccination campaign was launched, the lines on the chart began to diverge, and the number of deaths outside nursing homes continued to rise, while deaths in nursing homes fell sharply.
In order for this to be considered solid evidence of the effect of the vaccine, a study that analyzes the data and removes other possible factors is needed. But Mario Margolles, director of the Asturian Health Observer, has little doubt as to what the numbers mean. “It simply came to our notice then [the vaccines] have an effect because all other factors are equal and we see a decline in mortality from the first dose. When we see that, we are very excited and it gives us a feeling of great relief, ”he says. A third wave of coronavirus hit Asturias somewhat later than the rest of Spain, and according to Margolles, that meant the vaccine had more time to impact and prevented hundreds of deaths. Margolles also admits that the urge to immunize has shown that vaccines are not 100% effective. As studies show, they do not work in at least 5% of cases. “We see some cases getting infected more than a week after the second dose, but that was to be expected,” he explains. However, studies have shown that those who become infected with the coronavirus after receiving the vaccine have a much lower viral load, which means that the virus causes less serious symptoms or none at all, and the level of transmission is lower.
English version of Melissa Kitson.