Infections after the COVID-19 vaccine, what is behind?
Currently, COVID-19 approved vaccines have different degrees of proven effectiveness, researchers at the University of Florida found that the efficacy of the vaccine against the virus was of 54% on average. This means that, although the probability is low, it is possible to get the virus even after receiving the corresponding doses of the vaccine.
In this sense, there are two circumstances that can cause the virus to develop after having been vaccinated, as described by the Robert Koch Institute (RKI): if the infection occurred shortly before or in the first days after vaccination. This, since the body needs about two weeks after the full application of the vaccine to develop full immune protection.
In this way, although small, there is a margin of possibility for a vaccinated person to become infected with the COVID-19 virus, so it is necessary to continue the biosecurity measures to avoid possible infections.
What do figures say?
In the United States, the Centers for Disease Control and Prevention reported 5,800 cases of infections after receiving the vaccine, when the total number of vaccinees was 66 million. That is, an incidence of 0.0088%.
Of these 5,800 cases, 29% contracted the disease in an asymptomatic way, and only 7% required hospitalization. On the other hand, the death toll was 74, or 1.3% of those infected. In this regard, of the 66 million vaccinated, 0.0001% died of COVID-19, and a majority of those who were infected, did so with mild symptoms.
On the other hand, researchers from the United Kingdom Public Health Agency (PHE) crossed information from three databases and showed that, of 365,447 households, 24,217 were positive days after being vaccinated against COVID-19. That is, 4,107 infected, or 1.12% of the total. On the other hand, none of the cases needed hospitalization.
How to interpret the infections?
Figures show a minority percentage of infections and deaths after receiving the vaccine, which shows that, “vaccination is working exactly as we expected,” as Jinlene Chan, Maryland’s acting assistant secretary of public health services told the Wall Street Journal.
David Hirschwerk, an infectious disease physician at Northwell Health System (New York), told the Wall Street Journal that: “The experience so far is that the vaccine remains highly effective, and those who have been infected [despite being vaccinated] have had very mild and treatable diseases. This is really what we see every year with the flu vaccine”.
This shows a positive balance following the application of the COVID-19 vaccine, which minimizes risk and reduces the numbers of infections and deaths from the virus; but which highlights a reminder that the virus is still present globally and care needs to continue, even after receiving the vaccine.
On the other hand, variants and the time after vaccination are other determining factors when talking about infections after the COVID-19 vaccine is given.
Researchers and health officers suspect that immunity to COVID-19 could decrease for long periods of time, possibly after a year or more of vaccine application, and the vaccine may not effectively protect against variants of the coronavirus that could arise and evolve.
Therefore, a vaccinated person may need a booster dose of the vaccine to remain protected against the original strain of the virus and emerging variants, like how a booster against other diseases is recommended, as for tetanus every 10 years, or as each year different flu vaccines are recommended.
However, the need and timing for COVID-19 booster doses has not been established at present. No additional doses are recommended at this time,” as said by the U.S. Centers for Disease Control and Prevention (CDC).
In this sense, it is likely that it is not necessary to update the vaccines to deal with the variants, according to real data from Qatar, where after studying the full application of some vaccines, these reduced infections by variants by 90% and 75%. In addition, effectiveness against hospitalization or death was of 97% for these strains.
What to expect?
In this way, although reduced, infections and deaths of people after receiving the COVID-19 vaccine are a reminder that, even vaccinated, people are at risk from the virus, because, although the effectiveness of vaccines provides protection, until collective immunity is achieved, all people, to a greater or lesser extent, will be prone to contagion.
Therefore, although projections are encouraging, it is necessary to continue to take biosafety precautions, such as the use of masks, constant hand washing and social distancing. And so, we would expect collective immunity to be achieved and science to move towards the new variants, so that the risk of infection after the vaccine is given is reduced.