STOCK PURCHASE AGREEMENT


         STOCK PURCHASE AGREEMENT ("Agreement"), dated as of October 11, 1996,
between North American Vaccine, Inc., a company organized under the laws of
Canada ("Company"), and Abbott Laboratories, an Illinois corporation
("Acquiror").

         This Agreement sets forth the terms and conditions upon which the
Company is selling to Acquiror, and Acquiror is purchasing from the Company,
350,000 common shares, no par value, of the Company ("Shares").

         In consideration of the mutual agreements contained herein, and
intending to be legally bound hereby, the parties hereto agree as follows:

                                   ARTICLE I.
                         PURCHASE AND SALE OF THE SHARES

         1.1 PURCHASE AND SALE OF THE SHARES. Subject to the terms and
conditions of this Agreement, the Company hereby sells and delivers to Acquiror,
and Acquiror hereby purchases and accepts from the Company, the Shares free and
clear of all mortgages, liens, pledges, security interests, encumbrances,
pre-emptive rights or other third party interests of any nature whatsoever.

         1.2 CONSIDERATION. Subject to the terms and conditions of this
Agreement, in reliance on the representations, warranties and agreements of the
Company contained herein, and in consideration of the delivery of the stock
certificates representing the Shares, the Acquiror hereby pays to the Company
$6,343,750 in immediately available funds, as full payment and consideration for
the purchase of the Shares.

         1.3 CLOSING. The Closing of the transactions contemplated by this
Agreement will occur at the offices of the Company located at Beltsville,
Maryland on the date hereof ("Closing Date").

                  1.3.1 At the Closing, the Company will deliver to the Acquiror
         a stock certificate or certificates representing the Shares with a
         restricted stock legend set forth thereon; and an opinion of counsel to
         the effect that the Shares have been duly and validly issued and are
         fully paid and non-assessable. The restricted stock legend shall read
         substantially as follows:

                  The shares evidenced by this certificate may not be offered or
                  sold, transferred, pledged, hypothecated or otherwise disposed
                  of except: (i) pursuant to an effective registration statement
                  under the Securities Act of 1933, as amended, (ii) to the
                  extent applicable, Rule 144 under the Act (or any similar rule
                  under such Act relating to the disposition of



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                  securities), or (iii) if, in the opinion of counsel to the
                  corporation, an exemption from registration under such Act is
                  available.

                  1.3.2 At the Closing, Acquiror will deliver by check or wire
         transfer, at the election of the Company, $6,343,750 in immediately
         available funds.


                                   ARTICLE II.
                  REPRESENTATIONS AND WARRANTIES OF THE COMPANY

         The Company hereby represents and warrants to Acquiror as follows:

         2.1 CORPORATE STATUS; AUTHORITY. The Company is a corporation duly
organized, validly existing and in good standing under the laws of its
jurisdiction of organization, and has all requisite power and authority to
execute, deliver and perform this Agreement, to consummate the transactions
contemplated hereby and otherwise to carry out its obligations hereunder. The
execution, delivery and performance of this Agreement and the consummation of
the transactions contemplated hereby have been duly authorized by all necessary
corporate action on the part of the Company.

         2.2 BINDING AGREEMENT. This Agreement constitutes the valid and binding
agreement of the Company, enforceable in accordance with its terms (subject, as
to the enforcement of remedies, to general equitable principles and to
bankruptcy, insolvency and similar laws affecting creditors' rights generally).

         2.3 NON-CONTRAVENTION; CONSENTS. The execution, delivery and
performance of this Agreement by the Company, does not, and the consummation by
the Company of the transactions contemplated hereby does not and will not,
constitute or result in (with or without the giving of notice or the lapse of
time or both) (A) a breach or violation of any provision of the articles of
incorporation, as amended to date, or by-laws, as amended to date, of the
Company, or (B) a breach or violation of, or a conflict with, or a default
under, or termination of, or an event permitting any other person to terminate,
or the acceleration of, or the creation or imposition of any lien, charge,
pledge, security interest or other encumbrance on any properties or assets of
the Company pursuant to (i) any provision of any contract, license or other
agreement binding upon the Company, or (ii) any law, rule, writ, injunction,
decree, regulation, treaty, ordinance or order, award or governmental permit or
license applicable to the Company, which violation, breach, default, termination
or acceleration would, individually or in the aggregate, have a material adverse
effect on the business, financial condition, results of operations, or business
prospects of the Company.



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         2.4  REPORTS.

                       (i) As of their respective dates, neither the Company's
Annual Report on Form 10-K for the fiscal year ended December 31, 1995, nor any
other document filed subsequent to December 31, 1995 (including, without
limitation, the Company's Quarterly Reports on Form 10-Q for the quarters ended
March 31, 1996 and June 30, 1996) under Section 13(a), 13(c), 14 or 15(d) of the
Securities Exchange Act of 1934, as amended, with the Securities and Exchange
Commission (the "SEC"), (collectively the "Reports"), contained any untrue
statement of a material fact or omitted to state a material fact required to b
stated therein or necessary to make the statements made therein, in light of the
circumstances under which they were made, not misleading. Each of the balance
sheets contained or incorporated by reference in the Reports (including in each
case any related notes and schedules) fairly presented, the financial position
of the entity or entities to which it relates as of its date and each of the
statements of operation, statements of cash flows and statements of
stockholders' equity, contained or incorporated by reference in the Reports
(including in each case any related notes and schedules), fairly presented, the
results of operations, stockholders' equity and cash flows, as the case may be,
of the entity or entities to which it relates for the periods set forth therein
(subject, in the case of unaudited interim statements, to normal year-end audit
adjustments that are not material in amount or effect), in each case in
accordance with generally accepted accounting principles consistently applied
during the periods involved, except as may be noted therein.

                       (ii) The Company has timely filed all reports,
registrations and statements, together with any amendments required to be made
with respect thereto, that it was required to file since December 31, 1995 with
the SEC.

         2.5 ABSENCE OF CERTAIN CHANGES OR EVENTS. Except as disclosed in the
Company's Reports, since December 31, 1995, there has not been any:

         (a) change in the financial condition, assets, liabilities, properties,
business or results of operations of the Company which, individually or in the
aggregate, has resulted or could result in a materially adverse effect;

         (b) event or condition of any type that has resulted or could result in
a materially adverse effect on the financial condition, assets, liabilities,
properties, business or results of operations of the Company.

         2.6 COMPLIANCE. Except as disclosed in the Company's Reports, the
Company is not in violation of its Certificate of Incorporation, Bylaws or any
laws, ordinances and regulations or other governmental restrictions, orders,
judgments or decrees, where any such violation (a) would impair or restrict the
Company's power or authority to issue and deliver the Shares as required by this
Agreement, (b) of such Certificate of Incorporation or Bylaws has or would have
a material adverse effect on the financial condition, assets, liabilities,
properties, business, or results of operations of the Company, or (c) is based
upon facts of which the Company is aware and where such violation has or would


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have a material adverse effect on the financial condition, assets, liabilities,
properties, business or results of operations of the Company.

         2.7 LITIGATION. Except as disclosed in the Company's Reports, there is
no action, suit, proceeding or investigation pending or currently threatened
against the Company, which singly or in the aggregate, if the subject of an
unfavorable decision, ruling or finding, would materially adversely affect the
financial condition, assets, liabilities, properties, business, or results of
operations of the Company.

         2.8 DELIVERY OF SHARES. The Shares are duly authorized, validly issued,
fully paid and non assessable. The sale of such Shares has not been registered
under the Securities Act of 1933, as amended ("1933 Act"). Such Shares have been
listed for trading on the American Stock Exchange, subject to official notice of
issuance.

                                  ARTICLE III.
                   REPRESENTATIONS AND WARRANTIES OF ACQUIROR

         Acquiror represents and warrants to the Company as follows:

         3.1 CORPORATE STATUS; AUTHORITY. The Acquiror is a corporation duly
organized, validly existing and in good standing under the laws of its
jurisdiction of organization, and has all requisite power and authority to
execute, deliver and perform this Agreement, to consummate the transactions
contemplated hereby and otherwise to carry out its obligations hereunder. The
execution, delivery and performance of this Agreement and the consummation of
the transactions contemplated hereby have been duly authorized by all necessary
corporate action on the part of the Acquiror.

         3.2 BINDING AGREEMENT. This Agreement constitutes the valid and binding
agreement of the Acquiror, enforceable in accordance with its terms (subject, as
to the enforcement of remedies, to general equitable principles and to
bankruptcy, insolvency and similar laws affecting creditors' rights generally).

         3.3 NON-CONTRAVENTION; CONSENTS. The execution, delivery and
performance of this Agreement by the Acquiror, does not, and the consummation by
the Acquiror of the transactions contemplated hereby does not and will not,
constitute or result in (with or without the giving of notice or the lapse of
time or both) (A) a breach or violation of any provision of the articles of
incorporation, as amended to date, or by-laws, as amended to date, of the
Acquiror, or (B) a breach or violation of, or a conflict with, or a default
under, or termination of, or an event permitting any other person to terminate,
or the acceleration of, or the creation or imposition of any lien, charge,
pledge, security interest or other encumbrance on any properties or assets of
the Acquiror pursuant to (i) any provision of any contract, license or other
agreement binding upon the Acquiror, or (ii) any law, rule, writ, injunction,
decree, regulation, treaty, ordinance or order, award or governmental permit or
license applicable to the Acquiror, which violation, breach, default,
termination or acceleration would, individually or in the aggregate, have a

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material adverse effect on the business, financial condition, results of
operations, or business prospects of the Acquiror.

         3.4 SECURITIES REPRESENTATIONS. Acquiror has received and reviewed a
copy of the Reports. Acquiror understands that the sale of the Shares has not
been registered under the 1933 Act. Acquiror further represents that it (a) has
such knowledge, sophistication and experience in business and financial matters
that it is capable of evaluating the merits and risks of an investment in the
Shares, (b) is acquiring the Shares for investment and fully understands the
nature, scope and duration of the limitations on transfer imposed by the
securities laws and (c) can bear the economic risk of investment in the Shares
and can afford a complete loss of such investment. Acquiror has had an adequate
opportunity to ask questions and receive answers (and has asked such questions
and received answers to its satisfaction) from the officers of the Company
concerning the business, operations and financial condition of the Company.
Acquiror has no contract, undertaking, agreement or arrangement, written or
oral, with any other person to transfer or grant participations in any Shares.
Acquiror acknowledges and agrees that the Company has no obligation to register
the resale of the Shares under the securities laws.


                                   ARTICLE IV.
                               GENERAL PROVISIONS

         The Company and Acquiror further covenant and agree as follows:

         4.1 WAIVER OF TERMS. Any of the terms or conditions of this Agreement
may be waived at any time by the party or parties entitled to the benefit
thereof but only by a written instrument signed by the party or parties waiving
such terms or conditions.

         4.2 AMENDMENT OF AGREEMENT. This Agreement may be amended, supplemented
or interpreted at any time only by written instrument duly executed by each
party hereto.

         4.3 PAYMENT OF EXPENSES. The Company shall pay all expenses incurred by
or on its behalf, and Acquiror shall pay all expenses incurred by or on its
behalf in connection with the preparation, execution and delivery of this
Agreement and the consummation of the transactions contemplated hereby
(including without limitation, the reasonable fees, disbursements and expenses
of their attorneys, accountants and advisors).

         4.4 CONTENTS OF AGREEMENT; BINDING NATURE. This Agreement sets forth
the entire understanding of the parties with respect to the subject matter
hereof. Any previous agreements or understandings between the parties regarding
such subject matter are superseded by this Agreement. All representations,
warranties, covenants, terms and conditions of this Agreement shall be binding
upon and inure to the benefit of and be enforceable by the successors and
assigns of the parties hereto.


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         4.5 NOTICES. All notices, requests, demands and other communications
required or permitted to be given hereunder shall be by hand-delivery, certified
or registered mail, return receipt requested; telecopier, or air courier to the
parties set forth below. Such notices shall be deemed given at the time
personally delivered, if delivered by hand or by courier; at the time received
if sent certified or registered mail; and when receipt acknowledged by receiving
telecopy equipment if telecopied.

         If to Company:                     North American Vaccine, Inc.
                                            12103 Indian Creek Court
                                            Beltsville, MD  20705

         If to Acquiror:                    Abbott Laboratories
                                            Ross Products Division
                                            625 Cleveland Avenue
                                            Columbus, OH  43215

         4.6 COMMISSIONS AND FINDER'S FEES. Each party represents and warrants
that none of them has retained or used the services of any individual, firm or
corporation in such manner as to entitle such individual, firm or corporation to
any compensation for brokers' or finders' fees with respect to the transactions
contemplated by this Agreement for which the other may be liable.

         4.7 SEVERABILITY. In the event that any one or more of the provisions
contained in this Agreement shall be invalid, illegal or unenforceable in any
respect for any reason, the validity, legality and enforceability of any such
provision in every other respect and of the remaining provisions of this
Agreement shall not be in any way impaired.

         4.8 COUNTERPARTS. This Agreement may be executed in two or more
counterparts, each of which shall be deemed an original, but all of which
together shall constitute one and the same instrument.

         4.9 GOVERNING LAW; JURISDICTION. This Agreement shall be governed,
construed and enforced in accordance with the internal laws of the State of
Delaware, excluding any choice of law rules that may direct the application of
the laws of another jurisdiction. Each party hereto hereby irrevocably consents
and submits to the jurisdiction of and the service of process from courts
sitting in Delaware for any and all actions arising out of or related to this
Agreement.

         4.10 NO THIRD PARTY BENEFICIARIES. Nothing in this Agreement is
intended nor shall it be construed to give any person, firm, corporation or
other entity, other than the parties hereto and their respective successors and
assigns, any right, remedy or claim under or in respect of this Agreement or any
provisions hereof.

         4.11 SURVIVAL OF WARRANTIES. The warranties, representations and
covenants of the Company and Acquiror contained in this Agreement shall survive
the execution and delivery of this Agreement and the Closing for a period of two
years and shall in no way be affected by any investigation of the subject matter
thereof made by or on behalf of the Acquiror or the Company.

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         IN WITNESS WHEREOF, this Agreement has been duly executed by the
parties hereto as of the day and year first above written.

                                        NORTH AMERICAN VACCINE, INC.


                                        By: /S/ SHARON MATES
                                            -------------------------
                                            Name: Sharon Mates, Ph.D.
                                            Title: President

                                        ABBOTT LABORATORIES

                                        By: /S/ THOMAS M. MCNALLY
                                            ----------------------------
                                            Name: Thomas M. McNally
                                            Title: Senior Vice President
                                                   Ross Products Division


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