Whooping Cough Vaccine Does Not Stop Spread of Disease in Lab Animals

first_imgThe current vaccine for whooping cough, or pertussis, may keep you or your baby healthy, but it may not stop either of you from spreading the disease, a new animal study suggests. Baboons can harbor and spread the disease even after receiving the vaccine, researchers have found. The study adds to growing evidence that the acellular pertussis vaccines, in which only parts of the pertussis bacterium are injected into the bloodstream to elicit a protective immune response, are not as good at controlling the disease as older, whole-cell vaccines were. However, a vaccine manufacturer argues that it’s too early to conclude that a similar effect occurs in humans.Pertussis starts out like a normal cough but causes severe coughing fits and can be lethal to infants. By the time of diagnosis, it is often untreatable with antibiotics. Historically associated with the slums of pre-World War II Europe and America, the disease has made a powerful resurgence in recent years. The United States alone experienced about 50,000 cases of pertussis last year, with 18 deaths, according to the Centers for Disease Control and Prevention. The increase could be due in part to more sensitive tools to diagnose pertussis that were widely introduced in 2010, or to pockets of children whose parents oppose vaccination. However, previous research also indicated that immunity in people vaccinated with the acellular vaccines, introduced in the 1990s, is less long-lasting than in users of the older, whole-cell vaccine.The current study goes a step further and suggests that people who get the newer vaccine may still become infected and spread the germ. Tod Merkel, a microbiologist, and colleagues at the Food and Drug Administration in Bethesda, Maryland, examined response to the acellular vaccine in infant baboons, an animal that responds to the bacterium responsible for pertussis similarly to people. The researchers infected four groups of baboons , each group containing three or four babies, by anesthetizing the animals and dripping a pertussis-containing solution into their noses. One group had already received the standard three doses of the acellular vaccine; a second received the whole-cell vaccine. Members of the third group had previously had whooping cough. Those in the fourth group had not had the disease and received no vaccine before being exposed.Sign up for our daily newsletterGet more great content like this delivered right to you!Country *AfghanistanAland IslandsAlbaniaAlgeriaAndorraAngolaAnguillaAntarcticaAntigua and BarbudaArgentinaArmeniaArubaAustraliaAustriaAzerbaijanBahamasBahrainBangladeshBarbadosBelarusBelgiumBelizeBeninBermudaBhutanBolivia, Plurinational State ofBonaire, Sint Eustatius and SabaBosnia and HerzegovinaBotswanaBouvet IslandBrazilBritish Indian Ocean TerritoryBrunei DarussalamBulgariaBurkina FasoBurundiCambodiaCameroonCanadaCape VerdeCayman IslandsCentral African RepublicChadChileChinaChristmas IslandCocos (Keeling) IslandsColombiaComorosCongoCongo, The Democratic Republic of theCook IslandsCosta RicaCote D’IvoireCroatiaCubaCuraçaoCyprusCzech RepublicDenmarkDjiboutiDominicaDominican RepublicEcuadorEgyptEl SalvadorEquatorial GuineaEritreaEstoniaEthiopiaFalkland Islands (Malvinas)Faroe IslandsFijiFinlandFranceFrench GuianaFrench PolynesiaFrench Southern TerritoriesGabonGambiaGeorgiaGermanyGhanaGibraltarGreeceGreenlandGrenadaGuadeloupeGuatemalaGuernseyGuineaGuinea-BissauGuyanaHaitiHeard Island and Mcdonald IslandsHoly See (Vatican City State)HondurasHong KongHungaryIcelandIndiaIndonesiaIran, Islamic Republic ofIraqIrelandIsle of ManIsraelItalyJamaicaJapanJerseyJordanKazakhstanKenyaKiribatiKorea, Democratic People’s Republic ofKorea, Republic ofKuwaitKyrgyzstanLao People’s Democratic RepublicLatviaLebanonLesothoLiberiaLibyan Arab JamahiriyaLiechtensteinLithuaniaLuxembourgMacaoMacedonia, The Former Yugoslav Republic ofMadagascarMalawiMalaysiaMaldivesMaliMaltaMartiniqueMauritaniaMauritiusMayotteMexicoMoldova, Republic ofMonacoMongoliaMontenegroMontserratMoroccoMozambiqueMyanmarNamibiaNauruNepalNetherlandsNew CaledoniaNew ZealandNicaraguaNigerNigeriaNiueNorfolk IslandNorwayOmanPakistanPalestinianPanamaPapua New GuineaParaguayPeruPhilippinesPitcairnPolandPortugalQatarReunionRomaniaRussian FederationRWANDASaint Barthélemy Saint Helena, Ascension and Tristan da CunhaSaint Kitts and NevisSaint LuciaSaint Martin (French part)Saint Pierre and MiquelonSaint Vincent and the GrenadinesSamoaSan MarinoSao Tome and PrincipeSaudi ArabiaSenegalSerbiaSeychellesSierra LeoneSingaporeSint Maarten (Dutch part)SlovakiaSloveniaSolomon IslandsSomaliaSouth AfricaSouth Georgia and the South Sandwich IslandsSouth SudanSpainSri LankaSudanSurinameSvalbard and Jan MayenSwazilandSwedenSwitzerlandSyrian Arab RepublicTaiwanTajikistanTanzania, United Republic ofThailandTimor-LesteTogoTokelauTongaTrinidad and TobagoTunisiaTurkeyTurkmenistanTurks and Caicos IslandsTuvaluUgandaUkraineUnited Arab EmiratesUnited KingdomUnited StatesUruguayUzbekistanVanuatuVenezuela, Bolivarian Republic ofVietnamVirgin Islands, BritishWallis and FutunaWestern SaharaYemenZambiaZimbabweI also wish to receive emails from AAAS/Science and Science advertisers, including information on products, services and special offers which may include but are not limited to news, careers information & upcoming events.Required fields are included by an asterisk(*)As expected, the unvaccinated baboons developed severe whooping cough, while the baboons that had been sick previously remained well, the research team reports today in the Proceedings of the National Academy of Sciences. Both groups of vaccinated animals also remained healthy. However, the germ persisted an average of 35 days in the throats of baboons vaccinated with the acellular shot, though it grew less thickly than it did in the throats of the sick, unvaccinated animals. Baboons vaccinated with the whole-cell shot harbored the germ for 18 days, and it did not grow at all in animals that previously had recovered from pertussis.In another experiment, two baboons that had received acellular vaccines were exposed to whooping cough germs and then each was put in a cage 2 days later with previously unexposed baboons. In both cases, the vaccinated animals transmitted the germ to their cage mates, who developed pertussis. Follow-up studies showed that animals vaccinated with the acellular shots did not generate sufficient numbers of a particular variety of white blood cell to fight the pertussis infection as well as those receiving the older vaccine.The researchers conclude that a new vaccine may be needed to provide so-called herd immunity, the ability of a community to stop an infection from spreading, and protect vulnerable babies from pertussis. “There’s a difference between protecting individuals from illness and bringing down the incidence of pertussis in the population,” Merkel says. “To do both we may need a different vaccine.”Sanofi Pasteur of Swiftwater, Pennsylvania, which makes one of the two acellular pertussis vaccines used in the United States, issued a statement cautioning that the study was not designed to evaluate the extent to which vaccination reduced transmission. “It cannot be said with certainty that these findings are directly applicable to humans,” the company said it its statement.But other scientists applauded the work. “This is a very strong paper, even though it is a small sample,” says James Cherry, a vaccinologist at the University of California, Los Angeles, who was not involved in the study. Cherry argues that the efficacy of the acellular vaccines in trials held in Europe and Africa in the 1990s appeared high because case definitions did not count people with mild infections. The acellular vaccine was introduced because of public concerns and lawsuits arising from the whole-cell vaccine, which sometimes caused high fever and even seizures.As for the claim that the new result may not be applicable to people, Merkel notes that, for ethical reasons, it may be difficult to duplicate the study in humans, as that would require purposefully exposing experimental subjects to a 3-month bout of pertussis.last_img read more

IPL 2016: Dwayne Smith takes a dig at weak Royal Challengers Bangalore bowling line-up

first_imgWest Indies all-rounder Dwayne Smith, who had proved his T20 exploits with the suspended Indian Premier League team Chennai Super Kings, was at it again during Sunday’s game against Royal Challengers Bangalore. (IPL Full Coverage) The Gujarat Lions opener, who played his first game in season nine yesterday, smashed a 21-ball 32 to give his team a flying start in chase of 181 against Virat Kohli’s men.  (Also read: Virat Kohli heartbroken despite maiden T20 century) Smith said they would have faced no difficulty even chasing down a 200-plus target since the Royal Challengers Bangalore attack lacks teeth.”Their bowling line up is not as strong and even a target of 200 runs could have been chased against them on this wicket,” Smith said after Lions beat RCB by six wickets, chasing 181 here last night. “We won the first three matches and then lost a match against Sunrisers Hyderabad, I am happy that Lions team has got back on winning track,” he added.Skipper Suresh Raina (28) and Dinesh Karthik (not out 50) made useful contribution with the bat in Lions’ victory. (Also read: Suresh Raina credits wife Priyanka for his success as captain) Smith said Kane Richardson’s over in which he fetched 25 runs was turning point of the match.”It’s my natural game to play aggressive and I looked to attack every bowler but Richardson’s over was turning point as we were chasing 180 runs and got 25 runs in his over. I got an opportunity for the Lions and I just took it and gave what I can,” he said.advertisementWhen asked about Australian batsmen Aaron Finch’s injury, Smith said “he would be fine soon”.Finch had struck three back to back fifties in Lions victory, he however could not bat in Lion’s six wickets win against RCB.”I don’t know exactly what has happened to him but I am sure he will be fine soon,” Smith added.(With inputs from PTI)last_img read more