A review of the literature on the efficacy and safety of the rhinovirus vaccine
The World Health Organization estimates that nearly 2 million people around the world have been infected by the H1N1 virus.
But while those numbers are still growing, the CDC and its partners have found no clear evidence that the vaccines have been effective in preventing or treating the pandemic.
And yet, more than a dozen years after they first came into effect, the two vaccines have shown no signs of diminishing in their effectiveness.
A team of researchers led by the University of Texas Medical Branch (UTMB) published a review of vaccine effectiveness in April 2018 that also found no evidence of a dropoff in effectiveness with time.
A second review in July 2018 similarly found no effect on effectiveness with a longer follow-up period.
A common theory is that the human immune system gets more active after exposure to a virus, and the longer the virus is circulating, the more potent the immune response.
But a team of scientists led by UTMB’s Daniel J. Wigley and Mark R. Pritchard of the University at Buffalo (UB) found no such effect for the vaccine, which was developed in collaboration with a large pharmaceutical company.
What’s more, both reviews also found that the vaccine was well tolerated and was safe to administer.
These findings, however, did not prevent the use of the two drugs by some people.
“There are a lot of concerns about the safety and efficacy of rhinospirus vaccines,” says Wigly and Pritchards co-author Brian S. Wysocki.
“And that’s one of the reasons why there’s a lot more research that needs to be done.”
The authors note that they found no data to support a decrease in the effectiveness of the vaccines over time or a reduction in the frequency of the vaccine’s side effects.
“The study was designed to be a prospective observational study that looks at the long-term effectiveness of two different vaccines,” Wysick says.
“But in the meantime, there’s no indication of a decline in efficacy.”
What does the Cochrane Collaboration have to say?
While the review team found no significant effect on efficacy, the authors found that “many of the published trials have used a different design to assess efficacy and, when they have, the results are generally conflicting.”
The Cochrane review also found evidence that, for some patients, the use or administration of the H2N2 vaccine led to improvements in symptoms but not in other aspects of the disease.
“This finding is in line with the previous Cochrane study that found no benefit from the combination vaccine in people with influenza and was not associated with an increased risk of death,” says Dr. Michael S. Lipsitz, director of the Cochran Collaboration’s influenza and pneumonia program.
“Although we don’t have enough data to draw definitive conclusions, the Cochron report is important because it provides a better understanding of the effectiveness and safety profiles of the various vaccines.”
In addition to Wysicks and Pitts, the other co-authors of the review were Dr. J. Andrew W. Smith of the London School of Hygiene and Tropical Medicine and Dr. David J. Parnell of the National Institute of Allergy and Infectious Diseases.
“We have to take into account that the data used to generate this conclusion was based on studies conducted in humans that are subject to limitations such as incomplete data collection, different doses, or different doses of the same vaccine,” says Smith, who also served as an interim lead author on the Cochlear implant study.
“It’s important to note that the Cochley findings are consistent with previous Cochran and other reviews of the efficacy of the vaccination.
They do not contradict those previous studies.”
In a statement, the University’s School of Medicine said the researchers’ conclusion was “not surprising,” given the lack of data on effectiveness of vaccines at the time.
“For the majority of patients, H1-N1 vaccines are effective and safe,” it said.
“However, there are some who are more sensitive to the effects of the influenza vaccine.”
And the authors point out that it’s possible that some of the people who took the H3N2 vaccination, who were more susceptible to influenza-related illness, could have experienced more complications or died.
“Because the study was conducted in a population of adults and included only those vaccinated during the pandemics, we can’t exclude the possibility that those who did not receive H3Ns had more adverse events, such as respiratory infections, than those who received the vaccine,” the statement said.
In the meantime in the United States, the H5N1 vaccine remains available for purchase through the Department of Defense.
The Department of Health and Human Services’ National Center for Immunization and Respiratory Diseases (NCIRSD) and the CDC have published their own analyses of the flu vaccine’s effectiveness.
The researchers who led the