THIS ANNOUNCEMENT AND THE INFORMATION CONTAINED HEREIN ARE RESTRICTED AND ARE NOT FOR PUBLICATION, RELEASE OR DISTRIBUTION, DIRECTLY OR INDIRECTLY, IN WHOLE OR IN PART, IN OR INTO THE UNITED STATES, AUSTRALIA, CANADA, JAPAN, THE REPUBLIC OF SOUTH AFRICA OR ANY JURISDICTION IN WHICH IT WOULD BE UNLAWFUL TO DO SO.

FURTHER, THIS ANNOUNCEMENT IS FOR INFORMATION PURPOSES ONLY AND SHALL NOT CONSTITUTE OR CONTAIN ANY INVITATION, SOLICITATION, RECOMMENDATION, OFFER OR ADVICE TO ANY PERSON TO SUBSCRIBE FOR, OTHERWISE ACQUIRE OR DISPOSE OF ANY SECURITIES IN HVIVO PLC OR ANY OTHER ENTITY IN ANY JURISDICTION. NEITHER THIS ANNOUNCEMENT NOR THE FACT OF ITS DISTRIBUTION SHALL FORM THE BASIS OF, OR BE RELIED ON IN CONNECTION WITH, ANY INVESTMENT DECISION IN RESPECT OF HVIVO PLC. PLEASE SEE THE IMPORTANT NOTICE AT THE END OF THIS ANNOUNCEMENT.

THIS ANNOUNCEMENT CONTAINS INSIDE INFORMATION FOR THE PURPOSES OF ARTICLE 7 OF THE MARKET ABUSE REGULATION (EU) 596/2014 AS IT FORMS PART OF UK DOMESTIC LAW BY VIRTUE OF THE EUROPEAN UNION (WITHDRAWAL) ACT 2018 ("MAR"), AND IS DISCLOSED IN ACCORDANCE WITH THE COMPANY'S OBLIGATIONS UNDER ARTICLE 17 OF MAR. IN ADDITION, MARKET SOUNDINGS (AS DEFINED IN MAR) WERE TAKEN IN RESPECT OF CERTAIN OF THE MATTERS CONTAINED IN THIS ANNOUNCEMENT, WITH THE RESULT THAT CERTAIN PERSONS BECAME AWARE OF SUCH INSIDE INFORMATION, AS PERMITTED BY MAR. UPON THE PUBLICATION OF THIS ANNOUNCEMENT, THIS INSIDE INFORMATION IS NOW CONSIDERED TO BE IN THE PUBLIC DOMAIN AND SUCH PERSONS SHALL THEREFORE CEASE TO BE IN POSSESSION OF INSIDE INFORMATION.

hVIVO plc

("hVIVO" or the "Company")

Result of Secondary Placing

hVIVO plc (AIM & Euronext: HVO), the world leader in testing infectious and respiratory disease products using human challenge clinical trials, announces that it has been informed by the Selling Shareholders that, further to the announcement made at 7 a.m. today (the "ABB Announcement"), they have successfully sold a total of 29,955,178 Placing Shares at a price of 28 pence per Placing Share. The Placing Shares in aggregate represent approximately 4.40 per cent. of the Company's issued share capital.

Capitalised terms in this announcement shall have the same meaning ascribed to them as in the ABB Announcement unless the context requires otherwise.

On completion of the Placing the Selling Shareholders, shall have the following resultant shareholdings:

1. Shares held by Cathal Friel are held through Raglan Road Capital Limited and Raglan Securities Limited, two companies owned and controlled by Cathal Friel, Pamela Iyer, Cathal Friel's spouse, and Horizon Medical Technologies Limited, an investment vehicle controlled by Cathal Friel.

The Selling Shareholders have agreed with Cavendish and Peel Hunt not to dispose of any further Ordinary Shares for a period of 12 months without the prior written consent of Cavendish and Peel Hunt.

The notification at the end of this announcement, set out in accordance with the requirements of MAR (as defined above), provides further details of the transactions.

The Placing was conducted through an accelerated bookbuild by Cavendish Capital Markets Limited ("Cavendish") and Peel Hunt LLP ("Peel Hunt") acting as placing agents. Proceeds of the Placing are payable in cash on usual settlement terms and the Placing is expected to settle on or around 21 February 2024.

For further information please contact:

Notes to Editors

About hVIVO

hVIVO plc (ticker: HVO) (formerly Open Orphan plc) is a rapidly growing specialist contract research organisation (CRO) and the world leader in testing infectious and respiratory disease vaccines and therapeutics using human challenge clinical trials. The Group provides end-to-end early clinical development services to its large, established and growing repeat client base, which includes four of the top 10 largest global biopharma companies.

The Group's fast-growing services business includes a unique portfolio of 11 human challenge models, with a number of new models under development, to test a broad range of infectious and respiratory disease products. The Company has world class challenge agent manufacturing, specialist drug development and clinical consultancy services via its Venn Life Sciences brand, and a lab offering via its hLAB brand, which includes virology, immunology biomarker and molecular testing. The Group offers additional clinical field trial services such as patient recruitment and clinical trial site services.

hVIVO runs challenge studies in London from its Whitechapel quarantine clinic, its state-of-the-art QMB clinic with its highly specialised on-site virology and immunology laboratory, and its clinic in Plumbers Row. To recruit volunteers / patients for its studies, the Company leverages its unique clinical trial recruitment capability via its FluCamp volunteer screening facilities in London and Manchester.

Notification and public disclosure of transactions by persons discharging managerial responsibilities and persons closely associated with them

Important Notice:

MEMBERS OF THE GENERAL PUBLIC ARE NOT ELIGIBLE TO TAKE PART IN THE PLACING. THIS ANNOUNCEMENT AND ANY OFFER OF SECURITIES TO WHICH IT RELATES ARE ONLY ADDRESSED TO AND DIRECTED AT (1) IN THE UNITED KINGDOM OR ANY MEMBER STATE OF THE EUROPEAN ECONOMIC AREA, PERSONS WHO ARE QUALIFIED INVESTORS WITHIN THE MEANING OF ARTICLE 2(e) OF EU REGULATION (EU) 2017/1129 AND ANY RELEVANT IMPLEMENTING MEASURES (AND, IN THE UNITED KINGDOM, ONLY TO THE EXTENT THE SAME FORM PART OF UK DOMESTIC LAW BY VIRTUE OF THE EUROPEAN UNION (WITHDRAWAL) ACT 2018); AND (2) IN THE UNITED KINGDOM, PERSONS WHO (I) HAVE PROFESSIONAL EXPERIENCE IN MATTERS RELATING TO INVESTMENTS WHO FALL WITHIN ARTICLE 19(5) OF THE FINANCIAL SERVICES AND MARKETS ACT 2000 (FINANCIAL PROMOTION) ORDER 2005 (AS AMENDED) (THE "ORDER"); OR (II) FALL WITHIN ARTICLE 49(2)(A) TO (D) OF THE ORDER OR (III) ARE PERSONS TO WHOM AN OFFER OF THE PLACING SHARES MAY OTHERWISE LAWFULLY BE MADE (ALL SUCH PERSONS REFERRED TO IN (1) AND, (2) TOGETHER BEING REFERRED TO AS "RELEVANT PERSONS"). THE INFORMATION REGARDING THE PLACING SET OUT IN THIS ANNOUNCEMENT MUST NOT BE ACTED ON OR RELIED ON BY PERSONS WHO ARE NOT RELEVANT PERSONS. ANY INVESTMENT OR INVESTMENT ACTIVITY TO WHICH THIS ANNOUNCEMENT RELATES IS AVAILABLE ONLY TO RELEVANT PERSONS AND WILL BE ENGAGED IN ONLY WITH RELEVANT PERSONS.

This announcement and the information contained herein is for information purposes only and does not constitute or form part of any offer or an invitation to acquire or dispose of securities in the United States, Canada, Australia, South Africa or Japan or in any jurisdiction in which such an offer or invitation is unlawful.

The Placing Shares have not been, and will not be, registered under the US Securities Act of 1933, as amended (the "Securities Act"), or under the securities laws of any State or other jurisdiction of the United States, and, absent registration, may not be offered or sold in the United States (as defined in Regulation S under the Securities Act) except pursuant to an exemption from, or in a transaction not subject to, the registration requirements of the Securities Act and the securities laws of any relevant State or other jurisdiction of the United States. There will be no public offering of the Placing Shares in the United States or elsewhere.

The Placing Shares have not been approved or disapproved by the US Securities and Exchange Commission, any state securities commission or other regulatory authority in the United States, nor have any of the foregoing authorities passed upon or endorsed the merits of the Placing or the accuracy or adequacy of this announcement. Any representation to the contrary is a criminal offence in the United States.

No prospectus, admission document or offering document has been or will be prepared in connection with the Placing. Any investment decision to buy securities in the Placing must be made solely on the basis of publicly available information. Such information is not the responsibility of and has not been independently verified by the Selling Shareholders, the Company, Cavendish, Peel Hunt or any of their respective affiliates.

Neither this announcement nor any copy of it may be taken, transmitted or distributed, directly or indirectly, in or into or from the United States (including its territories and possessions, any State of the United States and the District of Columbia), Australia, Canada, the Republic of South Africa or Japan. Any failure to comply with this restriction may constitute a violation of US, Australian, Canadian, South African or Japanese securities laws.

The distribution of this announcement and the offering or sale of the Placing Shares in certain jurisdictions may be restricted by law. No action has been taken by the Selling Shareholders, the Company, Cavendish, Peel Hunt or any of their respective affiliates that would, or which is intended to, permit a public offer of the Placing Shares in any jurisdiction, or possession or distribution of this announcement or any other offering or publicity material relating to the Placing Shares, in any jurisdiction where action for that purpose is required. Persons into whose possession this announcement comes are required by the Selling Shareholders and Cavendish and Peel Hunt to inform themselves about and to observe any applicable restrictions.

No reliance may be placed, for any purposes whatsoever, on the information contained in this announcement or on its completeness and this announcement should not be considered a recommendation by the Company, the Selling Shareholders, Cavendish, Peel Hunt or any of their respective affiliates in relation to any purchase of or subscription for securities of the Company. No representation or warranty, express or implied, is given by or on behalf of the Company, the Selling Shareholders, Cavendish, Peel Hunt or any of their respective directors, partners, officers, employees, advisers or any other persons as to the accuracy, fairness or sufficiency of the information or opinions contained in this announcement and none of the information contained in this announcement has been independently verified. Save in the case of fraud, no liability is accepted for any errors, omissions or inaccuracies in such information or opinions.

Cavendish, which is authorised and regulated by the Financial Conduct Authority in the United Kingdom, is acting only for the Selling Shareholders in connection with the Placing and will not be responsible to anyone other than the Selling Shareholders for providing the protections offered to the clients of Cavendish, nor for providing advice in relation to the Placing or any matters referred to in this announcement, and apart from the responsibilities and liabilities (if any) imposed on Cavendish by the Financial Services and Markets Act 2000, any liability therefore is expressly disclaimed. Any other person in receipt of this announcement should seek their own independent legal, investment and tax advice as they see fit.

Peel Hunt, which is authorised and regulated by the Financial Conduct Authority in the United Kingdom, is acting only for the Selling Shareholders in connection with the Placing and will not be responsible to anyone other than the Selling Shareholders for providing the protections offered to the clients of Peel Hunt, nor for providing advice in relation to the Placing or any matters referred to in this announcement, and apart from the responsibilities and liabilities (if any) imposed on Peel Hunt by the Financial Services and Markets Act 2000, any liability therefore is expressly disclaimed. Any other person in receipt of this announcement should seek their own independent legal, investment and tax advice as they see fit.

References to time in this announcement are to London time, unless otherwise stated. All times and dates in this announcement may be subject to amendment.

Certain statements in this announcement are, or may be deemed to be, forward-looking statements. By their nature, forward-looking statements involve a number of risks, uncertainties and assumptions that could cause actual results or events to differ materially from those expressed or implied by the forward-looking statements. These risks, uncertainties and assumptions could adversely affect the outcome and financial consequences of the plans and events described herein. No one undertakes any obligation to publicly update or revise any forward-looking statement, whether as a result of new information, future events or otherwise. Readers should not place any undue reliance on forward-looking statements which speak only as of the date of this announcement. Statements contained in this announcement regarding past trends or events should not be taken as representation that such trends or events will continue in the future.

Neither the content of the Company's website nor any website accessible by hyperlinks on the Company's website is incorporated in, or forms part of, this announcement.

Information to Distributors

Solely for the purposes of the product governance requirements of Chapter 3 of the FCA Handbook Product Intervention and Product Governance Sourcebook (the "UK Product Governance Requirements"), and disclaiming all and any liability, whether arising in tort, contract or otherwise, which any "manufacturer" (for the purposes of the UK Product Governance Requirements) may otherwise have with respect thereto, the Placing Shares have been subject to a product approval process, which has determined that the Placing Shares are: (i) compatible with an end target market of retail investors and investors who meet the criteria of professional clients and eligible counterparties, each defined in paragraph 3 of the FCA Handbook Conduct of Business Sourcebook; and (ii) eligible for distribution through all permitted distribution channels (the "Target Market Assessment"). Notwithstanding the Target Market Assessment, "distributors" (for the purposes of the UK Product Governance Requirements) should note that: the price of the Placing Shares may decline and investors could lose all or part of their investment; the Placing Shares offer no guaranteed income and no capital protection; and an investment in the Placing Shares is compatible only with investors who do not need a guaranteed income or capital protection, who (either alone or in conjunction with an appropriate financial or other adviser) are capable of evaluating the merits and risks of such an investment and who have sufficient resources to be able to bear any losses that may result therefrom. The Target Market Assessment is without prejudice to any contractual, legal or regulatory selling restrictions in relation to the Offer. Furthermore, it is noted that, notwithstanding the Target Market Assessment, Cavendish and Peel Hunt will only procure investors who meet the criteria of professional clients and eligible counterparties.

For the avoidance of doubt, the Target Market Assessment does not constitute: (a) an assessment of suitability or appropriateness for the purposes of Chapters 9A or 10A respectively of the FCA Handbook Conduct of Business Sourcebook; or (b) a recommendation to any investor or group of investors to invest in, or purchase, or take any other action whatsoever with respect to the Placing Shares.

Each distributor is responsible for undertaking its own target market assessment in respect of the Placing Shares and determining appropriate distribution channels.