In the United States, children’s vaccination rates have experienced a decrease, especially since the beginning of the Covid-19 pandemic. For the 2023-2024 school year, only 92.7% of children of infant garden age received the required vaccines, a fall with respect to 95% prior to the pandemic. In addition, the exemptions reached a 3.3%record, which is equivalent to approximately 80,000 unvaccinated children.
This decrease in the coverage of immunization has caused a resurgence of vaccination preventable diseases. A recent measles outbreak In western Texas affected more than 620 people, resulting in 64 hospitalizations and the death of two children. Health authorities have identified that vaccination rates in specific communities, such as Mennonites and some private schools, are significantly below the 95%federal objective, which has contributed to the propagation of the virus.
According to a new study, measles, as well as other previously eradicated diseases such as rubella and polio, could return one day to the United States. Posted in the magazine JAMAthe study used large -scale epidemiological models for Simulate the spread of infectious diseases In the country, analyzing different scenarios with different levels of child vaccination.
Regarding this work, Noemí López Perea, researcher at the National Center for Epidemiology (CNE -iscii), He explains, in statements to Science Media Center, that “through the use of mathematical models, the authors establish the possible scenarios they would face in the US in case of possible discharges in vaccination coverage, as well as the overwhelming increase in the number of cases, outbreaks, associated complications and deaths, to diseases that were already eliminated.”
The expert points out that “the fact of being able to quantify the impact on the decrease in vaccination coverage is the key value of the study, since it gives clear scientific arguments to be presented to health decisors, the sanitary workers involved and parents, which are ultimately those who decide to vaccinate or not their children.”
Prevent measles from being endemic
In this study, researchers determine that, even with current vaccination rates, measles could become endemic again, constantly circulating in the US. within the decades. If vaccination rates experience small decreases, this process could be accelerated.
However, a modest increase in vaccination coverage could prevent its return.
According to the simulation model based on current vaccination rates per state, measles could restore its Endemic character in 83% of the simulationswith an average time of 20.9 years and an estimate of 851,300 cases for a period of 25 years.
In a scenario where measles vaccination, papers and rubella (MMR) decrease by 10%, it is estimated that 11.1 million measles cases could occur in 25 years. Instead, With a 5% increase in the MMR vaccine coveragethe model predicts only 5,800 cases.
On the other hand, in the study they ensure that it is unlikely that other vaccination preventable diseases manage to restore their endemicity with current vaccination levels.
If children’s vaccination decreased by 50%, the model estimates that 51.2 million measles cases could be recorded for 25 years, 9.9 million cases of rubella, 4.3 million cases of polyomyelitis and 197 cases of diphtheria. In this scenario, the model also predicts 51,200 cases of neurological sequelae associated with measles, 10,700 cases of congenital rubella syndrome, 5,400 cases of paralitic polyomyelitis, 10.3 million hospitalizations and 159,200 deaths.
In this same scenario, Measles would become endemic to 4.9 yearsthe rubella in 18.1 years and the poliovirus would reach endemic levels in approximately half of the simulations (56%) at 19.6 years. In addition, it also reveals considerable variability in projections, depending on the characteristics of the American population.
These results underline the importance of maintaining a High coverage in children’s vaccination of routine to prevent the resurgence of preventable infectious diseases in the US.
