Parainfluenza Virus Vaccine

5 Jun

The  human parainfluenza virus (HPIV)  contains two  viral glycoproteins in  the  viral envelope. Human parainfluenza viruses are  closely  related to the  measles, mumps, and  respi- ratory syncytial viruses. Human parainfluenza virus type  3 is the  second leading cause of infant and  childhood respira- tory  disease (after RSV). Currently, no vaccine or antiviral is available. The  human parainfluenza virus was  first discov- ered  in the  1950s  (Japan: Sendai virus). Since  then, 4 types with numerous subtypes and   subgroups/genotypes have been  identified.

HPIV-3. Several approaches  to  vaccine development have been evaluated in recent years. Two separate live- attenuated  vaccines have been  under evaluation. The cold-passaged (cp) HPIV-3 vaccines are  cold-adapted, temperature-sensitive prospects. In  early studies, the cp-18  strain was  not  sufficiently attenuated  for  chil- dren, but  the  cp-45  strain showed more  promising re- sults. When given  intranasally to children, the  vaccine candidate was  immunogenic and  safe  (319). The  anti- genically-related bovine  parainfluenza-3 (BPIV-3)  vac- cine  has  also  been  evaluated in  early clinical trials (320,321). Results revealed that  this vaccine is  safe, immunogenic, and  poorly  transmittable. In  addition, serum hemagglutination-inhibition antibody respons- es  were  increased with BPIV-3  when compared with those induced by cold-passaged HPIV-3. Trivalent sub- unit vaccines (322)  as  well  as  recombinant vaccines (323,324) are  also under evaluation as potential parain- fluenza vaccine candidates.

HPIV strains  are seasonal. HPIV-1 and   -2  usually cause respiratory outbreaks in  the  autumn. HPIV-3 may  cause croup, but  it may  produce symptoms that mimic   respiratory  syncytial  virus  infection with bronchiolitis  and   pneumonia being   common  symp- toms. HPIV-3 is  associated with spring outbreaks. HPIV-4  causes  mild   respiratory  infections and   is rarely  observed. HPIV   is  very  common and   almost all  children have had  HPIV  in  at least one  form  by age   6  years.  Children  are   most   at  risk, although bouts  of  HPIV   are   reported  in   foreign  travelers. Hence, the  elderly and  other immunosuppressed in- dividuals are  at risk.

Parainfluenza virus infections after hematopoietic stem cell transplantation occur  in 7–8% of cases with 78% of these infections being  community acquired. Three-fourths of these patients died  from pneumonia within 180 days  after pneumo- nia  was  diagnosed. Ribavirin and  intravenous immunoglobu- lin were  not effective treatments (325).

Random Posts

Comments are closed.