In contrast to data showing that the flu nasal spray was not very effective in preventing flu from 2013-2016, a new study by the American College of Physicians indicates that flu nasal spray offers similar protection against flu to the standard flu shot.
The most important step in preventing flu is to get a flu vaccination, while everyday preventative actions – such as covering coughs and sneezes and frequent hand-washing – can slow the spread of germs that cause flu.
The Centers for Disease Control and Prevention (CDC) recommend a yearly flu vaccine by the end of October for everyone over the age of 6 months. Vaccinating against flu can reduce flu illnesses, prevent flu-related hospitalizations, and protect people both individually and communally from becoming infected, known as herd immunity.
Current estimates reveal that the percentage of people who received an influenza vaccination during the past 12 months include 49.9 percent of children aged 6 months to 17 years, 31.2 percent of adults 18-49 years, 45.5 percent of adults 50-64 years, and 70 percent of adults 65 years and over.
There are several types of available flu vaccine options, such as the inactivated influenza vaccine (IIV) and recombinant influenza vaccine (RIV), which are both injected forms, and the live attenuated influenza vaccine (LAIV), also known as the “nasal spray” flu vaccine.
Recent observational studies have shown that the flu nasal spray is ineffective, which has led to the Centers for Disease Control Advisory Committee on Immunization Practices (ACIP) recommending that the nasal spray flu vaccine should not be used during the 2016-2017 flu season.
The results of that research showed that in the last flu season from 2015-2016, the nasal flu vaccine had no protective benefit for children ages 2-17. In comparison, the children that received the flu shot were 63 percent less likely to catch the flu than those people who were not vaccinated.
However, new research published in Annals of Internal Medicine found that immunizing children with the live attenuated influenza vaccine – the type found in the flu nasal spray – did not provide better direct or community protection against flu than the inactivated influenza vaccine, or standard flu shot. The protection was similar in both groups.
Previous studies conducted in young children suggest that the nasal spray vaccine provides better direct flu protection than the standard flu shot, which would also suggest better herd immunity. However, most comparative flu vaccine studies assess direct protection only and do not consider community protection.
Lead study author Dr. Mark Loeb, of McMaster University in Canada, and colleagues conducted the research in the Hutterite community – a colony where individuals live communally and are isolated from cities and towns. The team aimed to identify if vaccinating children and adolescents with the flu nasal spray would provide better direct and community protection than the standard flu shot.
Amongst 52 Hutterite colonies in Alberta and Saskatchewan, Canada, 1,186 children were assigned to receive the nasal spray vaccine and 3,425 to receive the standard flu shot.
The team found that the nasal spray vaccine offered similar direct protection to children and in creating herd immunity as the standard flu shot. Dr. Loeb notes that while the findings do not show the superiority of the nasal spray vaccine over the standard flu shot, what they do show is that both vaccines had a similar effect, which differs from the ACIP data.
The new recommendation against using the flu nasal spray is for the upcoming 2016-2017 flu season. However, the CDC review new data to maintain or change recommendations on a yearly basis.