{"id":28353,"date":"2025-11-17T12:54:49","date_gmt":"2025-11-17T20:54:49","guid":{"rendered":"https:\/\/www.skepticalraptor.com\/skepticalraptorblog.php\/?p=28353"},"modified":"2025-11-17T12:54:52","modified_gmt":"2025-11-17T20:54:52","slug":"intranasal-vaccine-for-bird-flu-shows-success-in-phase-1-trial","status":"publish","type":"post","link":"https:\/\/www.skepticalraptor.com\/skepticalraptorblog.php\/intranasal-vaccine-for-bird-flu-shows-success-in-phase-1-trial\/","title":{"rendered":"Intranasal vaccine for bird flu shows success in phase 1 trial"},"content":{"rendered":"\n

Although the bird flu<\/a> has been out of the news lately, it has not gone away, and researchers continue to develop a vaccine for the disease. The good news is that there are some promising early results for one intranasal (no needles) vaccine.<\/p>\n\n\n\n

This article will review bird flu and the new results of the phase 1 trial for an intranasal vaccine for bird flu.<\/p>\n\n\n\n

\"flock
Photo by Alexas Fotos on Pexels.com<\/a><\/figcaption><\/figure>\n\n\n\n

What is the bird flu?<\/h2>\n\n\n\n

Avian influenza, also known as “bird flu,” is a type A influenza subtype<\/a> designated as A(H5N1). The designation is based on antigens common to this influenza subtype.<\/p>\n\n\n\n

Avian influenza viruses are classified into subtypes, which are named according to subtle variations in the structure of two key proteins on the virus surface \u2014 hemagglutinin<\/a> (H) and neuraminidase<\/a> (N). The virus attaches to the hemagglutinin protein, allowing it to infect the cells. <\/p>\n\n\n\n

In general, H1 and H3 flu subtypes are best able to attach to human cells, while H5 is best at attaching to bird cells. However, H5 could mutate to become more effective at attaching to human cells, which would lead to human-to-human transmission of the disease.<\/p>\n\n\n\n

Another avian influenza is designated as A(H5N9), but the current bird flu outbreak appears to be the H5N1 subtype. Thus, H5N9 and H5N1 have the same hemagglutinin protein, but different neuraminidase proteins<\/a>.<\/p>\n\n\n\n

As the name implies, these viruses usually affect birds but can occasionally pass from birds to humans, cattle, pigs, and other animals. The H5N1 subtype arose in Asia a few years ago and has spread worldwide. It is highly pathogenic (meaning it can cause disease in humans) and has been passed to humans several times.<\/p>\n\n\n\n

Infected birds shed the virus through their saliva, mucous, and feces. Human infections with bird flu viruses occur when the virus gets into a person\u2019s eyes, nose, or mouth, or is inhaled. This can happen when the virus is in the air (in droplets or possibly dust) and a person breathes it in, or when a person touches something that has the virus on it and then touches their mouth, eyes, or nose. Human infections with bird flu viruses have occurred most often after unprotected contact with infected birds or surfaces contaminated with bird flu viruses. However, some infections have been identified where direct contact with infected birds or their environment was unknown.<\/p>\n\n\n\n

There are numerous cases where bird flu has been transmitted between humans<\/a>, but most human infections arise from constant contact with infected birds. Human infection with avian influenza A virus poses pandemic potential, so CDC and other public health agencies investigate every case to assess whether human-to-human transmission might have occurred. Detailed public health investigations can help determine whether person-to-person spread of an avian influenza A virus occurred.<\/p>\n\n\n\n

The signs and symptoms of bird flu infections in humans can range from nothing to severe. The infections are similar to other flu infections, including fever, cough, sore throat, runny or stuffy nose, muscle or body aches, headaches, fatigue, and shortness of breath.<\/p>\n\n\n\n

We don’t know much about the mortality rate from the bird flu. However, since humans lack immunity to the flu, a large outbreak or, worse, a pandemic, could lead to a much higher rate of hospitalization and death than the current circulating flu subtypes.<\/p>\n\n\n\n

\"scientist
Photo by Polina Tankilevitch on Pexels.com<\/a><\/figcaption><\/figure>\n\n\n\n

Bird flu intranasal vaccine study<\/h2>\n\n\n\n

In a paper published on 6 November 2025 in Nature Communications<\/a><\/em>, Justin R. Ortiz, MD, Center for Vaccine Development and Global Health, University of Maryland, Baltimore, and coauthors, studied the immune responses among the three groups that received one of three doses of the adjuvanted clade 2.1 influenza A\/H5 recombinant hemagglutinin glycoprotein (rH5) vaccine (Novavax<\/a>).<\/p>\n\n\n\n

The reason an intranasal vaccine was initially developed is that intramuscular flu vaccines trigger systemic immune responses that can prevent symptomatic illness, but they can be less effective at preventing transmission and infection. Intranasal vaccines, such as the one in this study, stimulate an immune response at the entry points where flu viruses infect the body. This may provide better protection against transmission and viral shedding. But assessing their systemic immune impact can be challenging.<\/p>\n\n\n\n

For this phase 1 clinical trial, the researchers randomized 40 healthy volunteers, aged 18-45 years, to one of five groups, each with eight individuals. Three groups received the rH5 vaccine at 25, 50, or 100 mcg, with a nanoemulsion adjuvant. One group received an unadjuvanted vaccine at 100 mcg, and the last group received a placebo. All groups received two doses, at day 1 and day 29. The trial ran from July 2022 to October 2023.<\/p>\n\n\n\n

All five groups had a low baseline immunity to H5N1. <\/p>\n\n\n\n

Here are the key results:<\/p>\n\n\n\n