Questions regarding the safety and duration of immunity following live yellow fever vaccination

Abstract

Introduction The World Health Organization (WHO) and other health agencies have concluded that yellow fever booster vaccination is unnecessary since a single dose of vaccine confers lifelong immunity. Areas Covered We reviewed the clinical studies cited by health authorities in their investigation of both the safety profile and duration of immunity for the YFV-17D vaccine and examined the position that booster vaccination is no longer needed. We found that antiviral immunity may be lost in 1-in-3 to 1-in-5 individuals within 5 to 10 years after a single vaccination and that children may be at greater risk for primary vaccine failure. The safety profile of YFV-17D was compared to other licensed vaccines including oral polio vaccine (OPV) and the rotavirus vaccine, RotaShield, which have subsequently been withdrawn from the US and world market, respectively. Expert Commentary Based on these results and recent epidemiological data on vaccine failures (particularly evident at >10 years after vaccination), we believe that current recommendations to no longer administer YFV-17D booster vaccination be carefully re-evaluated, and that further development of safer vaccine approaches should be considered.

Disease Resurgence, Production Capability Issues and Safety Concerns in the Context of an Aging Population: Is There a Need for a New Yellow Fever Vaccine?

“…Serious adverse events (SAE) including deaths occur following administration of YF vaccine [27,[94][95][96], and the frequency of vaccine-related SAEs for YF vaccine is comparable to the rate of vaccine-associated paralytic poliomyelitis with oral polio vaccine [97,98]. In addition, because YF vaccine is a live-attenuated vaccine produced in eggs, there are several contraindications and precautions to its administration [99].…”

“…A review of U.S. Vaccine Adverse Event Reporting System (VAERS) data from 2007-2013 found 3.8 SAEs per 100,000 vaccine doses [94], while a review of passive surveillance data from several non-endemic countries found rates ranging from 1.3 to 5.1 SAE per 100,000 vaccine doses [98]. The rate is known to increase with age such that 60-69-year old vaccine recipients had a rate of 6.5 SAEs per 100,000 doses while those over 70 years old had a rate of 10.3 [94].…”

Brazilian recommendations on the safety and effectiveness of the yellow fever vaccination in patients with chronic immune-mediated inflammatory diseases

“…A single-dose vaccination has been implemented since April 2017, however due to conflicting results on immunity in long-term YFV studies it is still under debate among vaccination experts [6,[18][19][20][21].…”

“…Studies published to date (WHO, ACIP, and CDC) have shown that approximately 88% of healthy individuals remain seropositive for more than ten years after the YFV [20]. On the other hand, Brazilian studies have demonstrated a fall in protection after 5-10 years in some groups [6,24].…”

Live Attenuated Yellow Fever 17D Vaccine: A Legacy Vaccine Still Controlling Outbreaks In Modern Day

“…Conversely, there is evidence of waning immunity in vaccinees in non-endemic areas, independent of exposure to related flaviviruses [27]. Additionally, it has been suggested that vaccinees who clear the virus without prolonged presentation of antigen to T cells and B cells may not mount a strong immune response, thereby failing to induce lifelong immunity [33]. …”